Category: Applications of Fiber Lasers

Breakthrough in laser-based chemical detection

A team of researchers from the USA designed a novel laser-based technique that allows the identification of electric charges and chemicals of interest with unprecedented sensitivity. This laser technology may have a potential application for scanning vast areas for radioactive material or dangerous chemicals for safety and security purposes.

This laser technique, called mid-infrared picosecond laser-driven electron avalanche, registers very low charge densities (the number of electric charges in a specific volume) in the air or other gases. The laser system technology makes it possible to measure electron densities in the air created by a radioactive source at levels below one part per quadrillion, which is equal to picking out one free electron from a conventional air molecule.

Calibration and detection range

The principle of operation is based on the use of a method enabling calibration of laser systems applied to examine irradiated air from 1 meter away. The researchers confirm that this laser technology could be used to identify other chemicals and species and could be improved for remote detection at distances of 10 meters and even 100 meters.

The process of electron avalanche

The laser system technique uses a process of electron avalanche, in which a laser beam accelerates a single free electron in a gas until it achieves enough energy to knock a different electron off a molecule, resulting in a second free electron. Also, the electron avalanche process repeats and converts into a collisional cascade that grows exponentially until the appearance of a bright observable spark in the laser beam focus.

Novelty of the mid-IR picosecond laser approach

Despite the fact that the method of laser-driven electron avalanche is not new, however, this is a new kind of high-energy, long-wavelength laser system — a picosecond mid-IR laser that is able to detect localized collisional cascades seeded only by the initial free electrons. It is possible to generate the original free electrons seeding the avalanches directly by laser protons when shorter wavelength laser beam pulses are applied.

Advantages over traditional detectors

This laser system technology overcomes conventional Geiger counters and scintillators, traditional detectors of radioactive decay products, because it resolves the problems of signal dropping at distances far from the radioactive source. Nonetheless, a laser beam allows researchers to remotely examine electrons created in the air near the source.

Future applications and improvements

Also, the researchers affirm that potential applications of the laser technique include the measurement of ultra-low charge densities from such sources as strong field physics interactions or chemical species. The presented laser technology is not ideal and requires improvements to make the technique more practical for use in the field.

Brain disorders and parvalbumin cells

Alzheimer’s disease and schizophrenia are considered to be the most common brain disorders, which are the result of problems in cells containing parvalbumin protein that represent almost one-tenth of all brain cells, but relatively little is known about their operation. Researchers from the USA have started to study the principle of cell operation by stimulating mouse brains with laser systems.

Custom-built fiber laser for brain research

A custom-built laser system has allowed the researchers from Washington University to find the connection among activity in specific inhibitory neural circuits, cerebral blood flow, and volume. Fiber laser demonstrated that higher activity, in particular inhibitory neural circuits, decreases cerebral blood flow and volume, while excitatory activity evokes blood flow and volume to increase.

Unexpected findings in blood flow and volume

The researchers discovered unexpected changes in blood volume and flow during stimulation of cells, including parvalbumin protein. The used laser technology is based on specially bred mice whose brains are stimulated with laser beam pulses.

Optogenetics technology and its advantages

The method of brain stimulation with light signals from the laser module, called optogenetics, has enlarged the understanding of brain operation as well as the brain processes of fear, sense of smell, and even the reason for drug addiction.

Mechanism of fiber laser stimulation

Optogenetics technology with a fiber laser system is convenient, less invasive, repeatable, and easy to use because this technique does not require putting any probes into the mouse brain. The principle of laser technology operation is quite simple; the researchers hit the necessary area of the mouse brain with the red colored laser beam, therefore, a desired neural circuit is activated.

Blood and oxygen response in neural circuits

More neurons are stimulated, and more blood and oxygen are produced. At the same time, the use of the laser system enabled to finding of the opposite response during the stimulation of parvalbumin-expressing cells. This connection between activity in specific neural populations and local changes in blood flow plays a crucial role in the regulation of blood supply by the brain.

Laser speckle contrasting imaging and measurements

The fiber laser technology reveals that parvalbumin-expressing cells are able to pull back and fine-tune the blood supply in areas where they are activated. A separate laser system technology, called laser speckle contrasting imaging, allowed researchers to measure the exact blood and oxygen levels that significantly reduced when parvalbumin cells were excited.

Long-range communication of parvalbumin cells

Parvalbumin cells were the way to transmit messages to faraway parts of the brain to change their hemodynamics, or blood flow, as well. In fact, the information obtained by the laser system will provide a better understanding of parvalbumin’s role in neurovascular coupling, demonstrating its influence on brain development or the emergence of neurological disorders.

Current medical applications of laser systems

The use of laser systems in medicine is not a new field of application; they are generally employed for the diagnosis of different diseases, in burn scar treatment, bioimaging, dental science, and various surgical procedures. Laser applications are not limited, and they continue to develop.

New research made by a group of scientists from the USA demonstrates that laser systems are able to make fluid containing blood cells act as an optical fiber cable under certain conditions, enabling to save the laser beam focus to be saved and make it shine through freely.

Potential diagnostic applications

Fiber laser systems can find new applications in medical diagnostic techniques that use the advantages of blood cell properties. These laser systems can be used for noninvasive imaging through the tissue, and the condition of the laser beam is able to provide deep penetration.

The application of laser systems for medical imaging, where getting light from the laser beam to support its shape and power over a distance plays a crucial role in making a precise diagnosis, is highly promising today, all over the world.

Experimental demonstration

The group of scientists experiments to prove their suggestions. They use a green laser system, shine its laser beam into a 3-cm-long vial filled with a suspension of human red blood cells. At the moment, when the laser power is increased, more light passes through the vial.

Use of optical tweezers in experiments

At the next level, the scientists employ a special device called an optical tweezer that allows them to measure the optical forces acting on individual blood cells. Due to advanced technologies, it is possible to demonstrate the principle of laser system operation that is based on the fiber laser that attracts cells into the laser beam and pushes them along the beam’s path.

Mechanism of laser focusing by blood cells

The principle of operation resembles the way that a lens focuses light by changing its path, while blood cells focus the laser beam and help it to penetrate deeper into the blood. Consequently, it is similar to an optical fiber cable that sends the light in a single direction.

Dependence on blood cell shape

This effect depends on the shape of blood cells. Red cells have the shape of a disc; however, they may shrivel or swell depending on the amount of salt. This laser system can find a potential application in diagnosing diseases such as sickle cell anemia and malaria.

Future improvements and potential

This research requires numerous improvements before it can be applied in a medical context. For example, it is necessary to optimize the high-quality laser beam for use in human tissues. At the same time, the laser system will be highly helpful in medical diagnostics and open new possibilities in deep-tissue imaging.

History of laser cutting technology

Laser system cutting is considered to be an industrial laser technology that is used in numerous fields. The first laser beams were introduced in 1960 when the physicist Theodore Maiman employed a synthetic ruby crystal to create the prototype that allowed making a straight laser beam. The technology of laser cutting was presented only in 1963 by the electrical engineer Kumar Patel, who used a CO2 laser, due to which laser system cutting became cheaper and more efficient.

The development of laser technology enables the mining industry to give laser systems a practical application; some laser modules are able to cut a 1-mm-thick steel sheet. CO2 laser systems are a common laser cutting device for cutting and engraving materials such as cardboard, plywood, MDF, or acrylic etc.

Laser cutting vs. laser engraving

The fact is that the processes of laser system cutting and engraving are both subtractive manufacturing techniques. A solid object is used in the process, and then the material is removed by the laser beam in order to produce a required image. These two laser technologies are not identical and have a distinction. A laser beam during laser system cutting hits the surface of a material and heats it up until it melts or vaporizes completely to leave a clean cut. The process of engraving by a CO2 laser is similar to cutting; the intensity of the laser beam is lower, and it only leaves a mark on the material’s surface rather than cutting it.

Key benefits of laser system cutting

Even though other technologies allow achieving similar results, laser system cutting offers the following benefits over other cutting techniques that include:

• high level of accuracy results in engraving more detailed images and cleaner cuts.
• high production speed;
• wide variety of materials that can be cut by the laser system without any damage;
• high accessibility compared to other techniques;
• the opportunity of laser application with any vector software;
• no wastes such as sawdust;
• laser technology for cutting purposes is very safe and reliable with the right equipment.

Laser system cutting is not yet ideal and needs some improvements to overcome other similar techniques.

Application of LIDAR in autonomous vehicles

High-performance laser system technology that enables the operation of light detection and ranging systems (LIDAR) has become a standard resource for the advancement of self-driving vehicles. The LIDAR technique relies on infrared laser systems, enabling autonomous vehicles to navigate by creating a real-time, 3D representation of their surroundings.

How LIDAR laser systems work

The laser technology includes the combination of pulsed fiber laser and single-pixel sensors or high-powered laser system flash illumination, applying the time of flight cameras to create the required 3D images. The laser system can carry out the travel time measurement of the light produced by a laser beam from the autonomous vehicle to the target and back to the vehicle.

Advantages of laser technology for LIDAR

This laser system technology offers a highly attractive benefit for LIDAR manufacturers, that is, increased laser system power, resulting in the opportunity for 3D maps to capture more objects and scenery from longer distances. The most important thing is eye safety, which is why short pulses produced by the laser beam play a crucial role.

Rapid pulsing (for example, more than 1 million times per second), more data points, and better signal quality are presented since the fast rise and fall times are essential.

Recent developments in LIDAR lasers

The recent development has the target to transmit LIDAR power emitted by the laser beam of 120W per channel “in a four-channel SMT package delivering >480W peak power with approximately 2 ns full-width half maximum (FWHM) pulses and <1 ns rise and fall times”.

Laser wavelengths used in LIDAR

LIDAR technology employs two primary wavelengths in laser systems: 905 and 1550 nm, each with its advantages. For example, a CMOS or other silicon detector can identify a 905 nm laser beam; the cost becomes lower, and the complexity is reduced. Laser systems at 1550 nm can be detected by silicon photomultipliers and, eventually, by indium gallium arsenide detectors; however, they present problems at the 105°C temperature required for automotive qualification, as well as challenges for eye safety.

Role of multichannel laser systems

Multichannel laser systems are necessary because the application of eight laser modules in individual firing will provide 1% resolution or 15 cm steps, whereas the minimum amplitude and dynamic range is virtually 18 dB when applying a 1 ns time of flight. In fact, based on the mentioned advantages, it is better to use 05 nm multichannel high-power lidar laser systems with nanosecond pulses.

Hybridized mode for reliability

There is an opinion that the presented laser technology should have a hybridized mode including short transmitted pulses with a slightly longer duration receiver “window”, resulting in a more reliable laser system. The main obstacle of LIDAR technology was overcome due to the opportunity to transmit shorter pulses that allowed for optimal eye safety, thermal management, and consequently, high resolution.

Advancement of dermatology with lasers

Laser technology has greatly advanced dermatology area resulting in strong help for practitioners that offer the best medical treatment for unique conditions, providing greater efficiency and safety. Laser system technology has promoted dermatology over the last few years, the development of laser systems and pulsed laser beam lights allows making the effective and safe treatment of different conditions like vascular and pigmented lesions, tattoos, scars, and so on.

Therapeutic applications of laser systems

Even though artificial laser beam light sources have been used for various skin disease treatments for a long time, the development of laser systems makes their application viable in therapeutics. The laser systems in dermatology allow carrying out reliable therapeutic applications in cosmetic rejuvenation and other conditions. The demand for popular laser technologies results in the development of improved laser systems with better features.

Surgical laser systems in dermatology

Surgical laser systems (especially CO2 lasers) are considered to be the most efficient in the dermatology area because of such features as precise wavelength, variable nature, and duration of output, making this type of laser suitable for the medical treatment of a wide range of skin and mucosal diseases.

For example, dye lasers offer numerous benefits for the treatment of such conditions as facial telangiectasias, spider veins, pyogenic granulomas, rosacea, and cutaneous vascular ectasia.

Principles of laser operation

The development of laser technologies makes surgery to carry out the controlled termination of the cutaneous target with minimal injury to the surrounding tissue. The principle of laser system operation is based on the maintenance of an appropriate wavelength during the laser treatment for preferential absorption by the required tissue. Moreover, the pulse duration of the laser beam should be shorter than the relaxation time of the target molecules.

Parameters for dermatological treatment

The choice of laser systems and pulsed laser beam light systems for dermatological treatment is based on the following parameters:

• Continuous-wave or CW fiber lasers are suitable for nonselective tissue damage due to the production of continuous laser beams.
• Compared to the previous one, Quasi-CW mode laser systems create interrupted emissions of light energy by shuttering the laser beam into shorter intervals.
• Intense pulse light lasers enable to treatment of vascular lesions due to their ability to target intravascular oxyhemoglobin.

These laser systems as pulsed dye laser, potassium titanyl phosphate, alexandrite, neodymium-doped yttrium aluminum garnet, and diode lasers, can be used for the reliable treatment of small and large blood vessels.

Introduction to the technology

A team of researchers from Australia developed a technology based on high-powered fiber lasers that is considered to be the first of its kind, resulting in the opportunity of pretransfusion testing out of the pathology lab and into point of care. The new fiber laser technology allows for improving pretransfusion testing; this fiber laser reduces blood incubation time from today’s standard of five minutes to 40 seconds.

The process of blood transfusion plays a critical role in numerous hematological conditions such as cancer, bleeding trauma, childbirth, and major surgery. The new fiber laser system enables the prevention of fatal blood transfusions for critically ill patients, even in the case of mass trauma. Additionally, high-powered fiber lasers are able to determine fetus-killing antibodies in pregnant women.

Effectiveness in critical situations

The fiber laser technology can be especially effective when such factors as time and precision are vital, for instance, in critical and emergency events like mass trauma, where it is necessary to perform pretransfusion testing quickly in order to save lives. Compared to high-powered fiber lasers, the traditional incubation technique requires more time, resulting in a remarkable effect on the survival chance of a patient.

Operating principle of the fiber laser system

The operating principle of the developed fiber laser system is based on “the laser incubation model in which a targeted illumination of a blood-antibody sample in a diagnostic gel card is converted into heat by way of photothermal absorption”. The high-powered fiber laser can heat he 75-μL blood-antibody sample to 37 °C in under 30 seconds.

Photothermal effects and rapid testing

The near-infrared fiber laser incubation demonstrates that red blood cells act as photothermal agents, causing fast antigen-antibody binding with no considerable damage to the cells or antibodies for up to 15 minutes. Therefore, the technology based on high-powered fiber lasers performs immunohematological testing faster and more sensitively than current best techniques; clearly positive results are shown from incubations of just 40 seconds.

Applications in pregnancy and antibody testing

The fiber laser system helps to discover the role of incubation time and temperature of the IgG anti-D antibody and the Rh blood group system’s D antigen. These antibodies are responsible for the hemolytic disease when the mother’s and baby’s blood types are incompatible. Precise testing by high-powered fiber lasers for pregnant women’s antibodies is highly important to save the fetus or newborn.

History of marking techniques

The technology of marking on items is regarded as one of the oldest, since our ancestors put various markings and engravings on rocks and bones half a million years ago. Today, marking techniques performed by modern fiber laser systems remain an essential aspect of a business.

Early developments in marking technology

The first pneumatic device for marking was designed in the U.S. in 1973. It allowed people to understand the importance and vital application of marking to a business, resulting in the fiber laser marking area. The first laser systems were used for marking and engraving on metal. They offered low energy transfer efficiency and had a huge size, which is why they were soon replaced by the diode-pumped laser technology for marking.

Advantages of modern fiber laser marking systems

The new laser system offers such benefits as compactness and efficiency over the previous generation, leading to its use in numerous scientific applications. This marking machine was also improved, and the fiber laser-sourced marking machine has appeared. The fiber laser technology is widely used for marking and personalization in most industries due to its accuracy, higher cost-performance ratio, and extensive application on sophisticated parts.

Marking non-metal products

Additionally, there are laser systems for marking non-metal products. For instance, CO2 fiber lasers can be used for these purposes. “The marking industry has been advancing with the enterprises and becoming one of the essential parts for companies, especially those in industrial and manufacturing areas”.

Benefits for businesses

All business sectors can take advantage of marking by fiber laser systems. For example, fiber laser technology provides high-quality marking that is considered to be the biggest benefit over other marking techniques. The laser beam has a smaller size than physical engraving; the laser system is controlled by a computer, significantly increasing the accuracy. Modern fiber laser systems for marking enable the production of complex forms, making small figures and text readable.

Product personalization and brand promotion

Fiber laser marking allows every business to make its product unique to increase sales and promote better brand recall and loyalty. CO2 fiber lasers for non-metal materials help engrave unique text, graphics, and barcodes to distinguish your products from others, since personalization plays a crucial role for businesses now.

Efficiency and durability of laser marking

The ability of fiber laser systems to penetrate and engrave is another great benefit of laser marking because they favor reducing not only time but also costs in manufacturing as well. The quality and durability are not lost during the process of laser system marking.

History and significance of laser technology

More than 40 years have passed since the development of the first laser system, but this was enough to make quantum electronics one of the leading areas of science and technology. Numerous improvements of lasers and their application make it possible to obtain fundamentally new results in information systems and communications, in biology and medicine, in space, and in other scientific research.

Unique properties of laser beam emission

Laser beam emission is characterized by monochromaticity, sharp focus, due to which it is possible to concentrate laser beam energy and power at considerable distances, the ability to vary the modes of radiation from continuous to pulsed with different pulse durations, and finally, coherence and polarization. A unique combination of these properties allows realizing various interaction mechanisms – both thermal (plasma formation, ablation, evaporation, melting, heating), and non-thermal (spectral resonance) effects on matter, which affect complex atomic and molecular systems.

Early adoption in medicine

It is not unexpected that the concept of employing laser beam radiation in medicine seems to be one of the initial. Over the past years, fiber laser devices and techniques have been used in almost all sections of medicine. Fiber lasers are especially successful in surgery, therapy, and the diagnosis of diseases. At the same time, it was discovered that each type of laser system operation, each laser-medical technique requires a specific combination of basic parameters of laser beam radiation and knowledge of the mechanisms of its interaction with various tissues.

Main areas of fiber laser application

Today, there are three main areas of fiber laser application in medicine.

Non-invasive diagnostics

New methods of non-invasive diagnostics: optical coherence tomography is considered to be a promising method for the diagnosis of ophthalmic and cancer diseases, and laser spectral analysis of biomarker molecules in exhaled air for diseases of the gastrointestinal tract. 

It is these diagnostics that use such unique properties of laser beam radiation as high coherence and polarization, which distinguish it from ordinary, even monochromatic, light.

Therapy using fiber laser systems

The therapy by fiber laser systems is widely used: irradiation with low-intensity laser systems of poorly healing wounds or human blood; in combination with photosensitizers, low-energy fiber lasers are used to selectively destroy cancer cells, atherosclerotic plaques, and treat macular degeneration (photodynamic therapy).

Surgical applications

Powerful (high-energy) laser systems are used as a surgical tool in ophthalmology, otorhinolaryngology, urology, and cosmetology. The surgery uses high-intensity laser systems that cause irreversible changes in tissues: welding, evaporation, and ablation (removal and cutting).

External and intravenous laser therapy

The therapy by fiber laser systems is another area that has become most widespread in the whole world – irradiation with low-energy lasers of blood and poorly healing wounds.

Mechanism of external laser therapy

For external use, laser system treatment occurs by exposure to certain areas and points of the body. The light penetrates through the tissues to a greater depth and stimulates the metabolism in the affected tissues, activates the healing and regeneration of wounds, and there is a general stimulation of the body as a whole.

Mechanism of intravenous laser therapy

During intravenous fiber laser system therapy, the laser beam influences the blood through a thin light guide that is inserted into a vein. The intravascular effect of low-intensity radiation allows you to affect the entire mass of blood. This leads to stimulation of hematopoiesis, strengthening immunity, increasing the transport function of blood, and also helps to increase metabolism. Significantly positive effects in laser system therapy of angina pectoris, myocardial infarction, and other pathologies were obtained with the introduction of an optical fiber through which laser beam radiation was introduced into the patient’s elbow vein.

Coherence and polarization considerations

Fiber laser radiation differs from ordinary, even monochromatic light by its coherence and polarization. There is a misconception that these special properties are responsible for the observed clinical and photobiological effects. As the laser beam penetrates deeper into the biological tissue (skin, organ, blood), coherence and polarization persist only to a depth of 200-300 microns, and then these properties disappear, and incoherent and non-polarized, monochromatic radiation spreads. Consequently, the beneficial effects observed during laser system therapy of various diseases are caused not by some special properties of fiber laser exposure, but are similar to the action of ordinary unpolarized and incoherent light with an appropriate radiation wavelength.

Secondary radiation and deeper effects

Photons emitted by electrons of excited biomolecules form secondary radiation that propagates (scatters) in all directions and excites other biological tissue molecules, increasing the depth of effective exposure. Due to the diversity of biomolecules in the body, secondary radiation is broadband, incoherent, and non-polarized.

Role of blood and lymph transport

Another factor that increases the depth of effective exposure is the transfer of excited molecules by blood and lymph throughout the body. It can be assumed that at depths exceeding 3 cm, the main biological effect is exerted not by the primary, laser beam radiation, but rather by the secondary scattered broadband incoherent and non-polarized radiation.

Challenges in dose determination

It is also very difficult to determine in practice the dose of absorbed laser beam radiation, since the proportion of reflected and absorbed radiation depends on many factors, so some researchers believe that fiber laser system therapy is an art like all medicine.

Mid-IR fiber laser applications

Today, two applications of fiber laser selective excitation of material vibrational levels in the mid-IR region of the spectrum are distinguished: fiber laser surgery of soft and hard tissues and laser system evaporation of polymers for thin-film spraying. These fiber laser system applications are based on the ability of mid-IR lasers to cause thermal or thermomechanical changes in the materials being processed, which can be classified as phase changes rather than laser beam chemistry. Fiber lasers have great potential for creating precision surgical instruments, due to their ability to focus laser beam radiation into a small spot along the length. A larger penetration depth increases the number of damaged cells, while a shorter depth results in less material removal per pulse.

Surgical precision and ablation

The goal of laser beam ablation is to remove a specific part of the tissue, leaving the surrounding tissue biologically alive. Surgical requirements, however, are often the opposite: high ablation rates are required in dentistry, while they should be minimal in refractive ophthalmology; cutting vascular tissues (brain surgery) requires some amount of surface coagulation (“thermal damage”) to achieve hemostasis (stop bleeding), while for non-vascular tissue (cosmetology) wound healing is better when there is no thermal damage.

Photodynamic therapy (PDT) with fiber lasers

Laser systems are finding new applications in PDT, a new cancer treatment method. Unsuccessful attempts to control the development of cancer remain a major problem. The main goal for patients with an incurable disease is to delay the development of the tumor. If the tumor is not large, the fiber laser system thermal ablation may become the treatment.

Mechanism and applications of PDT

Photodynamic therapy (PDT) by laser systems is another minimally invasive strategy for the removal of tumors. The idea behind PDT is to use the toxicity of porphyrin to destroy tumors. Up to the present moment, it has mainly been used to treat superficial, malignant, or pre-malignant lesions of the mucous membrane, carcinoma of the bladder, tumors of the esophagus or bronchus, a tumor on the head or neck, accessible through the endoscope. In combination with special catheters and the development of new photosensitizers, PDT by fiber laser systems can be effective for patients with solid tumors and especially with liver metastases.