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Ultrafast lasers emit ultrashort pulses with the duration of femtoseconds or picoseconds. These types of lasers and their applications are researched in the field of ultrafast laser physics and ultrafast optics. Ultrafast lasers are highly useful in a number of scientific applications as the duration of the optical pulse approaches the timescale of atomic processes. These lasers provide new opportunities for observation because they deliver the energy very quickly. Picosecond lasers and femtosecond lasers belong to the category of ultrafast lasers.
Picosecond lasers emit optical pulses with a duration of 1 or some picoseconds. Most often mode-locked lasers provide ultrashort pulses. For example, a mode-locked Nd:YAG can generate 10 picosecond optical pulses. Picosecond fiber lasers need to be mode-locked to provide high repetition rate and short pulse duration. Other ultrafast picosecond lasers include Q-switched lasers and laser diodes.
Picosecond lasers and picosecond fiber lasers are used in various cosmetic procedures, like tattoo removal, in microfabrication, cutting of transparent materials, semiconductor manufacturing, range-finding, biomedical applications, like ophthalmic surgery, etc.
Femtosecond lasers emit optical pulses that are below 1 picosecond. The typical duration that femtosecond lasers provide is between 30 fs and 30 ps. The short pulses that are produced by these lasers are most often achieved by passive mode locking. Ultrashort duration of pulses is common among ultrafast fiber lasers that offer pulse duration of 50 to 500 fs. Femtosecond fiber lasers are in most cases mode-locked. Fiber solutions are cost-effective, but require extensive design efforts due to technical challenges.
Femtosecond lasers are widely used in material processing. A short pulse of a laser reduces the “heat affected zone” which maximizes the precision of material processing by reducing undesirable effects like splatter and resolidification of melted material. Other fields of application of femtosecond lasers are tissue modification and microsurgery, medical device manufacturing, biomedical imaging, imaging, and spectroscopy, etc.
Ultrafast lasers have been developing for three decades and are expected to develop in the future. The main features that are expected to improve are pulse frequency, power levels, and manufacturing costs.
Optromix is a fiber laser vendor that offers innovative laser products with great customizing abilities. We provide a range of femtosecond and picosecond fiber lasers; for further details, please contact us at info@optromix.com or +1 617 558 9858

Tunable fiber lasers’ main characteristic is the ability of the wavelength to be tuned or adjusted. This process is referred to wavelength tuning. Tuning of the fiber laser may occur over a wide range, which is highly desired for certain applications.
Tunable fiber lasers are called wavelength agile if the wavelength tuning may be performed with high speed. Fast wavelength tuning is important for dynamic environments in which the laser may be used. Generally, single frequency fiber lasers can be continuously tuned over a certain range; other laser types can be tuned to only access discrete wavelengths. Tuning of non-single frequency lasers over a large range leads to mode hops.
Among fiber lasers, rare-earth-doped fiber lasers have an ability to be tuned over a wide range of wavelengths. For example, ytterbium fiber lasers are tunable over tens of nanometers. Fiber lasers that are widely tunable are Raman fiber lasers.
Tunable fiber laser systems are used is a variety of different applications:

1. Spectroscopy

A high-frequency resolution of transmission recording is possible by using tunable lasers. Tunable fiber lasers are also used in LIDAR.

2. Laser cooling

Some methods of laser cooling require tunable lasers that can be adjusted very precisely.

3. Isotope separation

The process of isotope separation with the use of a tunable laser consists of adjusting the laser wavelength to atomic resonances first and later tuning it to a particular isotope to ionize it and deflect it with an electric field.

4. Optical fiber communications

Tunable fiber lasers are often used as a spare laser in case the main fixed wavelength laser breaks down. In this situation, a wavelength-tunable laser is tuned to the wavelength of a particular channel that has failed.

5. Optical frequency metrology

In optical frequency metrology, the laser needs to be stabilized to a certain standard, e.g. an absorption cell, an optical reference cavity.
If you would like to buy Optromix tunable fiber laser, please contact at info@optromix.com or +1 617 558 98 58.

Narrow linewidth lasers, or lasers that have a small optical linewidth, are usually single-frequency, with low RIN and high spectral purity as a result of low phase noise.
The most common types of narrow linewidth lasers are distributed feedback laser diodes and distributed Bragg reflector lasers. Ultra narrow linewidths can be achieved by using a single-mode fiber that contains a narrow-bandwidth fiber Bragg grating in a resonator. Special fiber Bragg grating used in distributed feedback lasers also allows for a narrow linewidth of a few kilohertz. Narrow linewidth lasers with high output powers can be achieved in the form of longer distributed Bragg reflector lasers. Other lasers that have a narrow optical spectrum include diode-pumped solid-state bulk lasers and external-cavity diode lasers.
Several difficulties emerge in the manufacturing of narrow linewidth lasers and ultra narrow linewidth lasers. First of all, achieving single-frequency operation is crucial to get narrow linewidth; the goal is a stable single-frequency operation without mode hopping over a relatively long period of time.
Secondly, minimizing noise influences from external sources is problematic. There are multiple ways of resolving a problem of external noise influences. A stable resonator setup with a protection against vibration may be used. Certain lasers require specific solutions; for example, a low-noise current source should be implemented into the operation of electrically pumped lasers; optically pumped laser should have a low-intensity noise pump source. A Faraday isolator is often used to avoid optical feedback.
Thirdly, the laser itself, its design in particular, should be manufactured with a goal of minimizing laser and phase noise. Long resonator and a high intracavity optical power can be beneficial to construct a narrow linewidth laser.
Narrow linewidth lasers have a variety of applications: strain and temperature fiber-optic sensors, gas detection, LIDAR, wind speed measurements. Ultra-narrow linewidth lasers are used in optical frequency metrology.
If you would like to buy Optromix narrow linewidth single frequency laser, please contact us at info@optromix.com or +1 617 558 98 58.

CW fiber lasers operate continuously, they constantly emit light, as opposed to lasers that operate with pulsed pumping. Fiber lasers are often the only ones to operate continuously, as fiber greatly increases gain efficiency. CW lasers typically function with an output of power that is constant, however, some power variations may occur due to mode beating; this is mostly true for non-single frequency lasers.
The continuous nature of a laser beam may be achieved through ionizing gas (like in CO2 lasers) just below a critical level to be in a plasma state; the output of such laser can be turned on and off by controlling the amount of power at the threshold. If the input of power is just above the threshold, the plasma will produce a laser beam. This is one of the principles behind CW fiber laser technology.
CW fiber lasers differ by their power levels:

• high power CW lasers;
• medium power CW lasers;
• low power CW lasers.

High power lasers, including high-power CW fiber lasers, are the most popular variety of all lasers. High power output is required for many different applications, some of them include large laser displays, LIDAR, particle acceleration, material processing and more. Despite a wide scale use of these lasers, it is not determined what exactly is a high power laser. Typically, an output of a few hundred watts will classify a laser as “high powered”. In some areas, however, an output of a few dozens of watts is considered high.
High power CW fiber lasers are inherently brighter than other laser systems due to the high power output. Another important benefit of these lasers is their versatility. Beam switchers, couples and sharers are readily available for high-powered fiber lasers and can be used for customization.
High power CW fiber lasers are most frequently used in optical sensing, optical tweezing, atomic trapping and cooling, spectroscopy, efficient second-harmonic generation and more.
The design of high-power fiber lasers often involves challenges. Their prime limitation is a thermal degradation of fiber coatings. The thermal effects make it more difficult to achieve high efficiency at high power output.
Other effects that become relevant during the use of high-powered fiber lasers include: 1) Raman scattering; 2) four-wave mixing; 3) Brillouin scattering; 4) conversion of pump power into heat that may potentially lead to laser crystal fracture.

Optromix offers a number of high-power CW fiber lasers suited for different applications. If you would like to buy CW high-powered fiber lasers, please contact us at info@optromix.com or +1 617 558 98 58.

Optical tweezers, also known as optical traps, were first introduced in 1986 and since then have been widely used in different applications, being particularly successful in the field of biological studies, where optical tweezers are used to study DNA sequences, interactions of proteins, etc.
Optical tweezers have been used in numerous studies which involve optical tweezers in order to trap single atoms, viruses, single-cell organisms, strands of DNA, bacteria, carbon nanostructures and many others. The manipulation and assembly of structures on a nanoscale are the most promising advances right now.
The main principle of optical tweezing lies in the fact that light carries momentum that is in proportion to its energy, and the direction of light is the same as the direction of propagation. After interacting with an object, light beam changes its momentum; same happens with an object after interaction with a beam of light – it undergoes a change of momentum by an equal amount. These interactions result in a reaction force, which acts on the object.
In most optical tweezer set ups, light is emitted by a laser beam which is focused on a particular spot. A trap, that is able to hold a small dielectric object, appears in the spot. The scattering force, that occurs when light hits the object and scatters by its surface, produces a momentum transfer that leads to the object being pushed to the beam of light. This method allows to trap an object in all dimensions.
It is critical that lasers used to create an optical trap are highly stable. Ytterbium lasers are often used in optical tweezer systems as they produce a stable and high-power laser beam which allows for interference-free optical trapping. Other properties of Yb lasers include:

• a simple electronic level structure;
• a small quantum defect, which provides an opportunity for high power efficiency;
• Yb lasers have a capacity for wide wavelength tuning;
• a low-noise beam that allows to create an optical trap in a precise spot.

All of these characteristics make Ytterbium lasers one of the most optimal options for light emitters in optical tweezer systems. These lasers have already been used in multiple studies that utilize optical trapping for capturing micron-sized particles and living cells, superior pointing stability being the main reason these lasers are chosen over other types.
Optromix provides Ytterbium lasers that can be used in optical tweezing with great efficiency. If you would like to purchase Ytterbium lasers, please contact us at info@optromix.com or +1 617 558 98 58.

Beam quality can sometimes be an overlooked quality of a laser; however, this characteristic provides several advantages, such as faster and finer-feature machining, better process quality and an increased depth of focus. High beam quality laser has strong focusing capabilities and allows for a longer working distance which means that these types of lasers can be used in rough working environments without damaging the optics and the laser itself.
Beam quality is defined by M2, which represents a ratio of the beam of the laser and the perfect beam; consequently, the closer M2 is to 1, the better the quality of the laser beam. High beam quality lasers have M2 of less than 1,3. Due to the aforementioned reasons, lasers with high beam quality are very precise as they can produce an optical spot down to 20 microns. The best beam quality is produced by single mode lasers with M2 values around 1,1 – 1,2.
High-quality beam lasers prove to be useful in a variety of different applications:

1. Micro machining

The fine-tune nature of high-quality beam lasers is used to conduct machining operations on a small scale – drilling, slotting, cutting, etc. Laser surface engraving, for instance, is a process of emergence of small cracks in a material (around 100μm in size) under the pressure of melting and evaporation that occurs when a laser beam hits a surface.

2. Surface scrubbing

High beam quality provides consistency in scrubbing quality and high tolerance to defocusing during removal of thin materials from other films or a substrate. The low M2 does not result in quality degradation when the laser defocuses. The defocusing of a system occurs due to an uneven working surface, and lasers with high M2 can potentially result in a decreased production yield.

3. Removal of skin pigment and dye

High beam quality lasers are used to remove skin pigmentation and tattoos.
Generally, gas lasers, like CO2 lasers, exhibit a high beam quality. Optromix CO2 lasers demonstrate outstanding results in processing different types of materials with varied thickness. In Optromix, we aim to provide the best experience to our customers, and we will configure your laser system exactly according to your requirements. If you would like to buy high beam quality lasers, please Contacts at info@optromix.com or +1 617 558 98 58.

 

Narrow linewidth fiber lasers with fiber output connectors are widely used as laser sources in high sensitive optical fiber sensing fields, such as submarine hydroacoustic detecting and distributed acoustic sensing.
Currently, the practical optical fiber hydrophone system is based on the optical fiber interferometer technology. A multi-wavelength narrow linewidth laser or a laser array composed of multiple single-wavelength narrow linewidth lasers, where the multiple wavelengths should be in the international telecommunication union (ITU) grid, is needed for the large scaled hydrophone array.
The laser array composed of multiple single-wavelength laser modules is always cumbersome and complicated in the configuration. Consequently, a laser with the multi-wavelength output is attractive for its compact structure and usability. In recent years, the narrow linewidth fiber laser with the compact structure has been realized in distributed feedback (DFB) fiber laser where a short phase shifted fiber grating in erbium-doped fiber as the distributed feedback laser cavity assures the robust single longitudinal mode operation. This distributed feedback fiber laser can be used as a sensing element in the high sensitive acoustic detecting field and has been extensively studied previously. However, since the linewidth of the DFB fiber laser is very sensitive to the ambient noise, the precise temperature control for each cavity, the sound isolation packages for each cavity, and the whole laser configuration are necessary to make it stable and practical.
As for the wavelength number that this configuration can realize, it depends on the pump threshold of each laser cavity, the loss in the array, and the required power uniformity of the laser output. If the wavelength number increases, the power uniformity is more difficult to control. Usually, the pump threshold of the cavity is very low and much smaller than 5 mW, normally ~1mW.
Currently, the eighth-wavelength laser with 120-mW total power and 1.2-dB power difference within the wavelengths is obtained. Scientists expect that more wavelengths should be realized through reducing the loss in the array and adjusting the structural parameters of the laser cavities to meet the requirement in the larger scaled optical fiber sensing. The prototype based on this laser configuration is just in progress in the lab.
Optromix Company priority is to deliver the highest quality laser systems to our clients; we manufacture unique lasers for your specific needs.
If you would like to buy Optromix narrow linewidth fiber lasers, please Contacts at info@optromix.com or +1 617 558 98 58
 

Nowadays, optical scientists have generated ultrashort laser pulses in an optical fiber by using a method previously considered as physically impossible to achieve. Pulses can be generated in fiber lasers by a system known as a saturable absorber. When the light intensity is low, the absorber blocks light; when it is high, it lets it through. Since in femtosecond pulses the light intensity is much greater than in a continuous beam, the parameters of the absorber can be adjusted so that it only lets through such pulses. To generate higher energy femtosecond pulses in the optical fiber, the Warsaw physicists decided to improve saturable absorbers of a different type that relies on nonlinear optical effects causing a change in the refractive index of glass.
A nonlinear artificial saturable absorber works as follows. At the input, linearly polarized light is divided into a beam with a low intensity and a beam with a high intensity. The medium of the absorber can be chosen so that both light beams to experience a slightly different refractive index: that is, for them to travel at slightly different (phase) velocities. As a result of the velocity difference, the plane of polarization starts to rotate. At the output of the absorber, a polarization filter only lets through waves oscillating perpendicularly to the plane of polarization of the incoming light. When the laser is operating in continuous mode, the light in the beam is of a relatively low intensity, an optical path difference does not occur, the polarization does not change, and the output filter blocks the light. At a high enough intensity typical for femtosecond pulses, the rotation of polarization causes the pulse to pass through the polarizer.
The key performance figures of femtosecond lasers are the following:

1. the pulse duration (which is in some cases tunable in a certain range)
2. the pulse repetition rate (which is in most cases fixed, or tunable only within a small range)
3. the average output power and pulse energy

Optromix company offers few types of powerful femtosecond fiber lasers with high-frequency pulses. Amplifier compact size, no need to make adjustments when installing and air-cooling system allow using the femtosecond laser for industrial (OEM) and scientific purposes. Laser characteristics are optimal to perform ophthalmic surgery, spectroscopy, and micromachining. If you would like to buy Femtosecond Fiber Laser Series, please Contacts at info@optromix.com or +1 617 558 98 58

The main laser parameters are:

• Amplitude Noise (RIN). Dominates in direct detection scheme particularly in analog systems Frequency or Phase Noise;
• Frequency Stability;
• Output Power;
• Tuning Range (Frequency).

In frequency modulation (FM) formats phase or frequency, fluctuations compete with the signal. Reducing these fluctuations increases a signal to noise ratio. A laser signal may be used to interrogate path length changes in sensors such as a fiber Bragg grating (FBG) or Mach-Zehnder interferometer (MZI). If the frequency or phase of the laser changes it appears as a change of the path length thus degrading the signal to noise ratio.
There are different types of low phase noise lasers:
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Optromix Company offers CW fiber laser modules for OEM integration: single mode green and single frequency fiber laser modules. The laser module is particularly suited for OEM system integration when a compact design and remote beam delivery are critical factors. The laser part and the optical head can be ordered separately, which offers high flexibility to the customer in designing a laser projection system.
The module includes fully integrated laser control electronics, as well as continuous monitoring of the laser performance.
The single frequency fiber laser module is available in two different laser versions, Erbius-SF and Irybus-SF. Moreover, the laser offers a wide thermal wavelength tuning range and can be combined with fast wavelength modulation e.g. for external stabilization. The single frequency fiber laser modules key parameter is an ultra-narrow linewidth (< 100 kHz) based on the longitudinal single mode. Continue reading