Category: Fiber Laser Technology

Ultrashort laser pulses and their challenges

The generation of ultrashort laser beam pulses needs careful monitoring of the light’s dispersion provided by a fiber laser. There is a dependency of phase velocity and frequency; a real laser beam pulse includes a spread in frequency, which will enlarge as it goes through an optical medium. Thus, simple, low-cost sources of sub-picosecond laser beam pulses, soliton fiber laser systems, including a laser diode and an optical fiber, are considered to become an ideal solution.

Balancing dispersion with Kerr focusing

This type of laser system allows decreasing the spread by “balancing it against Kerr focusing – the narrowing of a laser beam pulse caused when light’s electric field alters the medium’s refractive index – so each pulse travels as a soliton, and its duration remains unchanged.”

Limitations of traditional soliton fiber lasers

Soliton fiber lasers are regarded as very promising because of such benefits as simple construction; they are not able to reach the high energies of techniques, for instance, chirped-pulse amplification.

Overcoming energy constraints with new technology

New fiber laser technology allows overcoming these limitations. The operating principle of the fiber laser is based on the application of a spatial light modulator to manage the light’s dispersion relation to enabling higher laser beam energy pulses. A dispersion relation demonstrates how a wave’s frequency is relevant to its wavelength. “For light in a conventional soliton laser, the function is approximately quadratic, and its second derivative describes how a laser beam pulse would spread in the absence of Kerr focusing.”

Role of higher-order dispersion

Researchers from Australia have demonstrated that higher-order dispersion provides real benefits. A photonic crystal waveguide based on fiber laser technology has been developed, where the effects of second- and third-order dispersion were suppressed due to the waveguide’s geometry. The balancing process of fourth-order dispersion with Kerr focusing is connected to soliton formation.

Programmable spatial light modulators

The soliton fiber laser system acts by applying the same principle. The researchers employed a programmable spatial light modulator instead of a specially designed waveguide to produce the required dispersion profile. Additionally, the researchers claim that the energy of the quartic laser beam pulses is regarded as proportional to τ−3, as predicted for fourth-order dispersion solitons.

Modern laser systems in microscopy

Modern laser systems in microscopy allow researchers to discover how molecules within a cell react and interact when it comes to investigating tumor growth. Laser beam microscopy requires to be labeled with fluorescent substances that make them visible to researchers; however, it may misrepresent the molecule behavior. New microscopes based on fiber laser technology operate without the need to label the molecules.

Design of the new fiber laser microscope

A team of researchers from Germany and China designed a microscope that includes a unique compact fiber laser instead of the solid-state laser systems that used to be applied. The microscope based on fiber laser technology produces less noise than conventional designs, allowing them to be used in operating rooms.

Advantages of fiber laser microscopy

Label-free microscopy in biomedical research

Usually, staining with fluorescent markers can not be performed on in vivo tissues; label-free microscopy plays a crucial role in understanding how different new types of cells develop from stem cells, as well as in differentiating a tumor from normal tissue without staining. Fiber lasers allow researchers to operate without markers in the muscle tissue cells of the heart and liver, as well as other cells.

Comparison with solid-state laser systems

Advanced fiber laser systems find their wide application in optical nanomicroscopes, in which laser beam light is transmitted through glass fibers rather than through a solid body of crystal or glass. Previously, solid-state laser systems surpassed fiber lasers because of their higher power and less noise. Researchers used two synchronized optical resonators (laser beam cavities), the wavelengths of which were required to hit the specimen through the lens at the same time, resulting in challenging control of the whole process.

Practical benefits of the new system

The developed fiber laser microscope presents an essential benefit that includes easier operation than a conventional solid-state laser system. This fiber laser system is less subject to error, and the process becomes faster because it does not need to label the molecules. The prototype of the fiber laser microscope promotes the development of portable devices that can be applied in the operating room, for example, to mark tumor borders during an operation.

Future applications in medicine

The new fiber laser technology provides benefits for numerous biomedical applications, and the early detection of tumors is only one specific example of this. It is planned to employ the new fiber laser microscope in clinical applications in the near future, because preliminary studies have already been conducted and demonstrated amazing results.

Role of fiber lasers in quantum technologies

Numerous quantum laser technologies imply the application of narrow-linewidth tunable diode lasers, amplified and frequency-doubled laser systems, frequency combs, and wavelength meters. Fiber lasers play a crucial role in quantum technologies. For instance, the laser systems are considered to be a product of the first quantum revolution, but their use is not limited to just optical quantum technologies. The fiber laser systems are widely utilized in numerous quantum setups.

Laser sources as the foundation for quantum networks

Laser beam light sources create the basis for quantum networks, i.e., “photons are regarded as the natural carriers of quantum states over long distances.” Laser systems are important in the production of such devices as quantum computers, quantum sensors, and optical clocks. Fiber laser technology offers total control over all degrees of freedom of the laser beam light, quite often at the quantum limit, resulting in an incredible way to start, manipulate, and read out various quantum tools.

Key qualities of fiber laser systems

Laser systems provide such qualities as wavelength, linewidth, power, polarization, temporal, and spatial laser beam profiles. A single-frequency fiber laser system is not always suitable for several applications.

Applications in atom control and cooling

For example, two phase-locked laser systems allow operating transitions in atoms that a single fiber laser could not manage. The laser beams can be applied as optical traps in order to direct the movement of the atoms. One more application includes cooling atoms as far as the absolute ground state, required in total control over the spectral qualities.

Scaling quantum computers with fiber lasers

High-powered laser beams are essential when scaling quantum computers, where it is necessary to address each ion individually. Fiber laser systems are perfect in operation with optical amplifiers, for example, semiconductor-based tapered amplifiers, and spectral qualities provided by laser technology enable them to inherit. “Starting from a single laser system that is tailored to offer the required, very specific spectral qualities, laser beam splitting and concatenation of tapered amplifiers provides the necessary scalability.”

Multiple laser systems in complex setups

It is not surprising that numerous setups are needed for several fiber laser systems (some a dozen of them), all with various properties, taking into account the relevance and versatility of lasers for quantum technologies. Certain applications of quantum computers require a few laser systems of the same type in one setup, increasing the total number to tens of lasers.

Introduction to industrial fiber laser technology

A team of scientists from the U.S. presented a new fiber laser technology that allows for industrial laser systems to emit attosecond laser beam pulses. Usually, attosecond science presents several difficulties because it is based on world-class fiber laser devices.

Accessibility advantages of industrial systems

The opportunity to apply industrial laser systems instead of complex devices that need huge laboratory tools and cleanroom environments enlarges new possibilities, resulting in higher accessibility to researchers from all spheres. The generation of short laser beam pulses required for attosecond research needs the light to be directed through tubes filled with noble gases (xenon or argon) to compress them in time.

Nonlinear compression for attosecond pulses

The scientists claim that nonlinear compression performed by the fiber laser is considered to be efficient when driven in molecular gases, employing laser beam pulses substantially longer than a few cycles, because nonlinearity is increased.

Testing and pulse compression

The fiber laser technology has already been tested, and the scientists have succeeded in compressing about 100-cycle laser beam pulses generated by an industrial fiber laser system by applying molecular gases – nitrous oxide in the tubes leading to a change in pulse length.

Molecular alignment and supercontinuum generation

These laser systems allow for simultaneously driving molecular alignment and supercontinuum generation in a gas-filled capillary. Pulses of single-cycle laser beams are considered feasible to produce with this fiber laser technology. Industrial laser systems that can be easily bought at an appropriately accessible price now are applied to emit attosecond pulses.

Importance of gas choice and pulse duration

The choice of gas and the durations of the laser beam pulses play a crucial role. For example, the use of molecular gas results in an enhanced effect. Therefore, the choice of gas is “important since the rotational alignment time depends on the inertia of the molecule, and to maximize the enhancement we want this to coincide with the duration of our pulses generated by the fiber laser.”

Prospects of attosecond fiber lasers

The development of fiber laser technology makes the system adjustment simpler, promoting the operation with a wide variety of laser systems with various parameters. The research of attosecond science is regarded as very promising because such fiber lasers make it possible to construct images of the electrons and study the fast motion of electrons inside atoms.

Importance of low-noise signals

Low-noise signals play a crucial role in various applications, for instance, high-speed telecommunication and ultrafast data processing. Usually, huge and sensitive microwave oscillators emit these signals; however, these systems can not be applied outdoors. The promising solution is the application of high-quality pulsed laser systems based on micro-comb technology.

Advantages of micro-comb fiber lasers

This type of fiber lasers offers the high optical frequency and spectral purity of laser beam fields; they produce low-noise microwaves compactly and efficiently. These laser systems emit microwaves with limited frequency adjustment, which is why conventional resonator has to be huge and have difficulties in tunability.

Novel micro-comb laser technology

A team of scientists from Dublin presented a novel fiber laser technology for producing different low-noise microwaves with a single system. According to this technology, a microresonator frequency comb is installed into a compact laser system, whose “intensity  is modulated by an off-the-shelf microwave oscillator.”

Tunable microwave generation

It is possible to emit new laser beam microwaves with tuned frequencies by forcing the modulation frequency to tightly follow a subharmonic frequency of the microwave. These microwaves provide lower phase noise than fiber laser systems used previously for the same purposes.

Frequency division and spectral purity

This fiber laser technology has a frequency division that allows for delivering the frequency purity of an optical signal into the microwave domain. It is possible to deliver the spectral purity between various microwave signals. Although it is challenging to perform ideal laser beam microwave frequency division in a tunable way, the fast-modulated fiber laser allows for making it by employing cost cost-effective photodetector and a moderate control system.

Spectroscopic applications and system components

This laser system produces a secondary frequency comb with more densified spectral emissions, leading to numerous spectroscopic applications. Additionally, the main elements of the system, for example, the microresonator and the semiconductor laser system, are considered to be discrete and connected with lengthy optical fibers.

Integration and miniaturization

The team now continues working on integrating and advanced-packing the system. The opportunity to make the device smaller and its mass production leads to a revolution in the market for portable, low-noise microwave and frequency comb tools.

Introduction to the fiber laser scalpel

A team of researchers from Taiwan and Russia presented a new scalpel based on fiber laser technology. The fiber laser scalpel is twice as thin as conventional ones. Taking into account the fact that standard medical scalpels have different shapes for specific tasks, the new laser system provides numerous benefits.

Benefits of decreased thickness

The researchers have developed a scalpel based on a fiber laser system that allows for decreasing its thickness by half. The researchers claim that the created curvilinear shape opens numerous opportunities for fiber laser applications in medical fields.

Design and innovation in the laser scalpel

The team from Taiwan and Russia produces a laser beam “blade” applied in a medical scalpel with a given curved shape employing a photonic “hook”. There are laser beam scalpels only with an axisymmetric focus area, that is, their blade is cylindrical.

New blade shapes for medical applications

Another blade shape enables the researcher to open new applications of the laser system in medicine. This fiber laser scalpel is two times thinner than the cylindrical shape. Therefore, specific tasks require various shapes of standard surgical scalpels.

Operating principle of the fiber laser scalpel

It is possible to cut or remove tissue with a scalpel based on fiber laser technology. The operating principle is based on the laser beam with increased temperature in a limited range up to 400°С. Thus, the fiber laser system burns out the beam, while tiny blood vessels along the cut edges are sealed.

Advantages of the curved laser beam

The fiber laser scalpel provides incredible advantages; for example, the incisions made by it are pretty thin, and the radiation is not dangerous. The researchers have succeeded in bending the laser beam by the installation of an amplitude or phase mask at the end of the optical fiber.

Role of the optical mask

The mask in the fiber laser system is regarded as a small plate made of metal or dielectric material, for example, glass. The laser beam energy inside the optical fiber is redistributed by the mask, leading to a curved part of radiation localization at the end of the fiber (the so-called photonic hook).

Testing and results

The fiber laser system has already been tested and demonstrated that the curved blade has a length of up to 3mm. The thickness of the laser beam blade reaches 500 microns (slightly bigger than the diameter of a human hair). Test results make the fiber laser scalpel perfect for surgeries.

Expanding applications of fiber laser technology

Laser systems become an integral part of human life; fiber laser technology continues to develop, leading to the appearance of new applications and expanding the old ones. For instance, a team of scientists from Japan has presented novel linear nanomotors that can be moved in controlled directions by applying a laser beam.

Role in microfluidics and lab-on-a-chip systems

These fiber lasers used in nanomotors make it possible to develop new microfluidics and lab-on-a-chip systems with optically actuated pumps and valves or other devices based on fiber laser technology that can be previously challenging or even impossible to perform.

Challenges of nanoscale devices

Nanoscale devices greatly differ from the ones involving the contraptions that researchers have used to employed. For example, it is more challenging to produce and accurately control a nanomotor (the tiny motor that is smaller than a bacterium) based on the laser system than to drive a car.

Development of gold nanorod-based motors

The recent development of the Japanese team includes a fiber laser system used in linear motors made from gold nanorods that allow for moving in a controlled direction when subjected to a laser beam. The operating principle is similar to a sailboat that can be directed in any desired position.

Principles of nanomotor operation

Such nanomotors’ operation does not lead to following the direction of the laser beam. Their operation is based on the orientation, even when they are subjected to a laser beam emitting from another angle. Thus, the laser system moves due to the lateral optical force produced by the sideways scattering of the laser beam from the particles.

Advantages of the new fiber laser system

There is no need to direct or shape the laser beam with lenses, which was quite challenging previously. Compared to previous systems, the wavelength of light produced by the fiber laser does not influence or limit the size of new nanomotors.

Key role of plasmon resonance

The laser beam or the field gradient does not define the motion and does not restrain it; the direction is based on the orientation of the nanoparticles themselves. “The key to this fiber laser technology is the localized surface plasmon resonance – collective oscillations of free electrons – within periodic arrays of nanorods.” They emit a scattered laser beam in a particular direction.

Future applications of nanomotors

The team of scientists plans to apply this fiber laser system to develop a new platform for nano-sized devices with moving parts that follow predetermined paths while being directed by unfocused laser beams. Thus, they claim the cost and complexity of such systems can be significantly reduced while accuracy and robustness will increase.

The challenge of coherence in fiber lasers

According to a team of researchers from Australia, the coherence of laser systems can be significantly improved by overcoming limitations that have been considered to be fundamental for 60 years. Fiber lasers produce highly directional, monochromatic, coherent laser beam light.

Importance of coherence

The light is produced by the laser system as a narrow laser beam in a specific direction. The wavelength and phase of every photon are equal. The coherence of a laser beam, in turn, is regarded as “the number of photons that can be emitted in this manner, which is a property crucial in determining the performance of a fiber laser in precision tasks like quantum computing.”

Historical quantum limits

A quantum limit of laser beam coherence is not a new phenomenon, and it was discovered in the 1960s. There is a theory that the coherence of the fiber laser system is less than the square of the number of photons. The researchers suggest a way to apply laser beam energy to the system and how it is released to create the beam.

Role of quantum mechanics

Even though these suggestions are suitable for most standard laser systems, they are not obligatory when it comes to quantum mechanics. The ability of researchers to develop and control quantum systems has transformed the conception of what is practical. Numerous studies allow for a better understanding of quantum processes occurring in fiber lasers.

Novel approach to overcome coherence limits

The team of researchers from Australia has applied numerical simulations to show that it is possible to overcome the limitations of fiber laser systems. The fiber laser technology has already been tested and demonstrated that the laser beam coherence is less than the fourth power of the number of photons.

Higher photon storage and quantum models

When the stored number of photons in the fiber laser is large, as is generally the case, the upper limit is much higher than before. Also, the researchers have developed a quantum mechanical model for a fiber laser system that could reach this upper limit for coherence in theory.

Future applications of quantum-limited fiber lasers

Much time is required to create a super laser system. However, this fiber laser technology proves that the production of a quantum-limited fiber laser is possible by employing the superconducting technique. This kind of technology is also applied in the modern best quantum computers.
The developed fiber laser may have applications in that field. Thus, new fiber laser systems allow for expanding new applications and promoting new research into more energy-efficient laser systems.

Novel fiber laser systems for cancer detection

Novel fiber laser systems have been developed by an international team of researchers to provide efficient detection of cancerous cells during the surgical process. The fiber laser is a part of a compact multimodal imaging system that enables testing tissue samples directly during surgery.

Combining imaging techniques in one system

Usually, microscopes based on fiber laser technology apply only one imaging technique (confocal microscopy, multiphoton microscopy, or Anti-Stokes Raman Spectroscopy). Nevertheless, their combination in a single fiber laser system provides faster and robust information about tissues and possible diseases.
Even though these techniques can lead to making excitation laser systems complex, large, and expensive, this research is very promising. The team plans to produce a fiber laser that emits several excitation wavelengths and various laser beam pulse durations. This fiber laser technology allows combining several techniques in one compact device.

Precise detection of tumor margins

The fiber laser system helps to test tissue samples directly after surgery or even during it, resulting in more precise detection of tumor margins. “Combining three methods allows superimposing several levels of information and thus obtaining a more precise picture of the cells.”
These fiber lasers provide a simpler way to distinguish cancerous cells from healthy ones. Now, researchers are developing an ultrashort laser beam pulse source for the new laser system. This source will synchronously pump two optical parametric oscillators.
It is planned that the fiber laser system will emit several laser beam outputs with tunable wavelengths. These laser beam pulses are generated in both the femtosecond and picosecond range. The fiber laser technology is considered to be very promising for the three imaging techniques in a multimodal system.

Advantages and future applications

It is required to produce a quick electronic system to monitor the fiber laser in the multimodal system. The laser system will operate with the microscope’s scanner technology. A benefit of a novel fiber laser system as favorable thermal properties remove the need for additional air-cooling.
Advantages of fiber laser technology make the imaging system less expensive, more energy-efficient, and smaller than traditional microscopes with titanium-sapphire laser systems. The potential applications of novel fiber laser systems include the detection of drugs and nanoparticles in tissues and cells, or the testing of cosmetic products.

Overview of fiber laser applications

Since the end of the last century, fiber lasers have been considered to be elements of different scientific directions, starting from the telecom market and ending with the medical procedure market. They are widely used in a variety of advanced and scientific laser applications.

Key features driving popularity

Different wavelength ranges, short pulse durations, nonreactivity to environmental conditions, small size, and other important factors of fiber laser designs play a crucial role in their popularity among the scientific and government communities. Fiber laser technology often solves problems that other modern technologies can not. Industrial fiber lasers are found in manufacturing, automotive, aerospace, transport, consumer devices, and other industries.

Evolution of fiber laser usage

From the very beginning, when the fiber lasers were implemented, they were in great demand for the processing of metals. Now they are applied for 3D printing, surface cleaning and modification, and many microprocessing methods of a great variety of materials.

Advantages of modern fiber laser modules

Fiber laser modules can provide higher output powers and laser beams of good quality. They encourage efficient energy consumption, resistance to vibration, and environmental conditions. That’s why it’s no wonder they make a fast return on investment.

Revolution in fiber laser technology

The first fiber lasers were mostly ineffective. But then new methods of delivering the pump light into the cladding were discovered. These methods allowed making fiber lasers more powerful and showing their true potential. It was a revolution in fiber laser systems, and the new era began. As a result of this revolution, fiber laser modules were adapted to mass production.

Future potential and reliability

Fiber lasers proved to be a reliable and powerful instrument for different applications. They are present in a wide range of different scientific spheres and directions. However, they still have a great development potential that continues to grow.