Infrared Laser System Research Articles

Ultra-broadband hybrid infrared laser system

A hybrid IR laser system consisting of molecular gas lasers with frequency conversion of laser radiation in a solid-state converter (nonlinear crystal) was developed. One of these gas lasers is a carbon monoxide laser operating in multi-line or single-line mode. Another one is a carbon dioxide laser operating in multi-line mode. The two lasers operate under Q-switching with a joint rotating mirror. Due to sum- and difference-frequency generation in nonlinear crystals, the laser system emits within wavelength range from 2.5 to 16.6μm. The laser system emitting radiation over such an extremely wide wavelength range (2.7octaves) is of interest for remote sensing and other applications connected with laser beam propagation in the atmosphere.

Multilayered structuring of thin-film PV modules by ultrafast laser ablation

Due to the growth of thin-film solar photovoltaic (PV) market for renewable energy sources, the development of versatile technique for scribing surface patterns with new record efficiency is crucial. This study presents an ultrafast-laser process for noncontact and chemical-free scribing of thin-film layers in CuInxGa(1−x)Se2 (CIGS)-based PV modules. The proposed ultrafast laser scribing process for single- and multiple-pass patterning was performed using an infrared laser system comprising a femtosecond laser source, galvano-mirror scanner, and high-precision motor driven stage. The interaction between laser beam and three thin films in CIGS-based PV modules was determined by investigating potential film-removal mechanisms, such as geometrical, thermal, mechanical, and optical properties. Well-defined grooves were successfully obtained on thin-film layers by applying pulse energies near the ablation threshold. The experimental results and numerical calculations show that the laser–material interactions indicate that the proposed surface-pattern technique is precise. The energy transfer between the laser beam and thin-film device was affected by introducing an electron–photon coupling variable. The study results show the surface-pattern characteristics of applying an ultrafast laser to thin-film PV modules under controlled process conditions.

A new technology for applanation free corneal trephination: the picosecond infrared laser (PIRL).

The impact of using a Femtosecond laser on final functional results of penetrating keratoplasty is low. The corneal incisions presented here result from laser ablations with ultrafast desorption by impulsive vibrational excitation (DIVE). The results of the current study are based on the first proof-of-principle experiments using a mobile, newly introduced picosecond infrared laser system, and indicate that wavelengths in the mid-infrared range centered at 3 μm are efficient for obtaining applanation-free deep cuts on porcine corneas.

Characterization of silicon micro-strip sensors with a pulsed infra-red laser system for the CBM experiment at FAIR

The Compressed Baryonic Matter (CBM) experiment at FAIR is composed of 8 tracking stations consisting of 1292 double sided silicon micro-strip sensors. For the quality assurance of produced prototype sensors a laser test system (LTS) has been developed. The aim of the LTS is to scan sensors with a pulsed infra-red laser driven by step motor to determine the charge sharing in-between strips and to measure qualitative uniformity of the sensor response over the whole active area. The prototype sensors which are tested with the LTS so far have 256 strips with a pitch of 50 μm on each side. They are read-out using a self-triggering prototype read-out electronic ASIC called n-XYTER. The LTS is designed to measure sensor response in an automatized procedure at several thousand positions across the sensor with focused infra-red laser light (spot size ≈ 12 μm , wavelength = 1060 nm). The pulse with duration (≈ 10 ns) and power (≈ 5 mW) of the laser pulses is selected such, that the absorption of the laser light in the 300 μm thick silicon sensors produces a number of about 24000 electrons, which is similar to the charge created by minimum ionizing particles (MIP) in these sensors. Laser scans different prototype sensors is reported.

双波长红外激光诱发痛觉刺激研究

双波长红外激光诱发痛觉刺激研究

High-resolution atmospheric pressure infrared laser desorption/ionization mass spectrometry imaging of biological tissue

An atmospheric pressure laser desorption/ionization mass spectrometry imaging ion source has been developed that combines high spatial resolution and high mass resolution for the in situ analysis of biological tissue. The system is based on an infrared laser system working at 2.94 to 3.10 μm wavelength, employing a Nd:YAG laser-pumped optical parametrical oscillator. A Raman-shifted Nd:YAG laser system was also tested as an alternative irradiation source. A dedicated optical setup was used to focus the laser beam, coaxially with the ion optical axis and normal to the sample surface, to a spot size of 30 μm in diameter. No additional matrix was needed for laser desorption/ionization. A cooling stage was developed to reduce evaporation of physiological cell water. Ions were formed under atmospheric pressure and transferred by an extended heated capillary into the atmospheric pressure inlet of an orbital trapping mass spectrometer. Various phospholipid compounds were detected, identified, and imaged at a pixel resolution of up to 25 μm from mouse brain tissue sections. Mass accuracies of better than 2 ppm and a mass resolution of 30,000 at m/z = 400 were achieved for these measurements.

Effect of IR Laser on Myoblasts: Prospects of Application for Counteracting Microgravity-Induced Muscle Atrophy

Microgravity-induced muscle atrophy is a problem of utmost importance for the impact it may have on the health and performance of astronauts. Therefore, appropriate countermeasures are needed to prevent disuse atrophy and favour muscle recovery. Muscle atrophy is characterized by loss of muscle mass and strength, and a shift in substrate utilization from fat to glucose, that leads to a reduced metabolic efficiency and enhanced fatigability. Laser therapy is already used in physical medicine and rehabilitation to accelerate muscle recovery and in sports medicine to prevent damages produced by metabolic disturbances and inflammatory reactions after heavy exercise. The aim of the research we present was to get insights on possible benefits deriving from the application of an advanced infrared laser system to counteract deficits of muscle energy metabolism and stimulate the recovery of the hypotrophic tissue. The source used was a Multiwave Locked System (MLS) laser, which combines continuous and pulsed emissions at 808 nm and 905 nm, respectively. We studied the effect of MLS treatment on morphology and energy metabolism of C2C12 cells, a widely accepted myoblast model, previously exposed to microgravity conditions modelled by a Random Positioning Machine. The MLS laser treatment was able to restore basal levels of serine/threonine protein phosphatase activity and to counteract cytoskeletal alterations and increase in glycolytic enzymes activity that occurred following the exposure to modelled microgravity. In conclusion, the results provide interesting insights for the application of infrared laser in the treatment of muscle atrophy.

Sentinel node biopsy in breast cancer using infrared laser system first experience with PDE camera

Background Sentinel node biopsy (SNB) is a gold standard in staging of early breast cancer. Nowadays, routine mapping of lymphatic tract is based on two tracers: human albumin with radioactive technetium, with or without blue dye. Recent years have seen a search for new tracers to examine sentinel node as well as lymphatic network. One of them is indocyanine green (ICG) visible in infrared light. Aim The aim of this study is to evaluate clinical usage of ICG in comparison with standard tracer, i.e. nanocoll, in SNB of breast cancer patients. Materials and methods In the 1st Department of Surgical Oncology and General Surgery, Greater Poland Cancer Centre, Poznań, 13 female breast cancer patients have benn operated since September 2010. All these patients had sentinel node biopsy with nanocoll (human albumin with radioactive technetium), and with indocyanine green. The feasibility of this new method was assessed in comparison with the standard nanocoll. Results A lymphatic network between the place of injection of ICG and sentinel node was seen in infrared light. An area where a sentinel node was possibly located was confirmed by gamma probe. Sensitivity of this method was 100%. Conclusion SNB using ICG is a new, promising diagnostics technique. This procedure is not without drawbacks; nevertheless it opens new horizons in lymphatic network diagnostics.

Dual-chirped optical parametric amplification for generating few hundred mJ infrared pulses

An ultrafast high-power infrared pulse source employing a dual-chirped optical parametric amplification (DC-OPA) scheme based on a Ti:sapphire pump laser system is theoretically investigated. By chirping both pump and seed pulses in an optimized way, high-energy pump pulses can be utilized for a DC-OPA process without exceeding the damage threshold of BBO crystals, and broadband signal and idler pulses at 1.4 μm and 1.87 μm can be generated with a total conversion efficiency approaching 40%. Furthermore, few-cycle idler pulses with a passively stabilized carrier-envelope phase (CEP) can be generated by the difference frequency generation process in a collinear configuration. DC-OPA, a BBO-OPA scheme pumped by a Ti:sapphire laser, is efficient and scalable in output energy of the infrared pulses, which provides us with the design parameters of an ultrafast infrared laser system with an energy up to a few hundred mJ.

Impact of Collateral Damage to Endourologic Tools During Laser Lithotripsy—In Vitro Comparison of Three Different Clinical Laser Systems

During laser lithotripsy, working instruments are often in close proximity to the distal fiber tip and may be damaged accidentally or even intentionally. The aim of this study was to compare the amount of damage to a standard guidewire and the nitinol wires of endourologic retrieval baskets that were affected by three different clinically available laser systems. The impact of pulsed laser irradiation on a standard hydrophilic guidewire and a retrieval basket were investigated. One infrared (IR) laser system (holmium:yttrium-aluminum-garnet [Ho:YAG]: λ = 2100 nm) and two laser systems emitting light in the visible (VIS) spectral range (frequency-doubled double-pulse neodymium:YAG [FREDDY]: λ = 532 nm/1064 nm and flashlamp pulsed dye [FLPD]: λ = 598 nm) were used. Experimental parameters were fiber core diameter, laser pulse energy, and distance between the fiber tip and the investigated tool. Damage was evaluated by microscopic investigation and by quantifying the damage size and magnitude by creating laser impact related damage factors. After application of one single laser pulse, IR-laser related maximum damage to guidewires occurred, depending on the pulse energy and the fiber core diameter, either in contact mode or in a distance of maximum 2 mm. Maximum VIS-laser related damage occurred in a distance range of 2 to 3 mm. The nitinol wires of the extraction tools could be destroyed completely by IR laser irradiation at pulse energies E(P) > 1200 mJ, depending on the fiber core diameter used. VIS lasers were solely able to set visible damage to guidewires without any disruption of nitinol wires. Ho:YAG laser induced damage to endourologic tools is significantly higher compared with the impact of the FREDDY or the FLPD-laser. Because complete disruption of guidewires and stone extraction tools occurred, a safety clearance must be kept between the fiber tip and the endourologic tool during Ho:YAG stone disintegration. If disruption is intended, such as in the case of basket-retrieval problems, it can easily be performed with Ho:YAG irradiation.

Carrier-envelope stabilized few-cycle infrared laser system

According to the feature of the passive carrier-envelope phase (CEP) stabilized idler of the optical parametric amplified process, a CEP stabilized three-stage collinear optical parametric amplifier is built. Millijoule ultrashort infrared output (1.4 mJ/40 fs/1 kHz at 1.8 μm) with CEP fluctuation ~516mrad is obtained from the system. After passing through a hollow-core fiber and block material, the pulses are finally compressed to less than two cycles (<12 fs), and the single pulse energy is 0.54mJ. The system provides an excellent laser source for the experiments of individual attosecond pulse generation and other high harmonic generation (HHG).

The Fabrication and Characterization of Organic Light-Emitting Diodes by Using Laser Patterned Anode

We fabricated blue fluorescent organic light-emitting diodes (OLEDs) by using a laser patterned ITO anode. An indium tin oxide (ITO) layer was defined directly with an infrared laser system (wavelength = 1064 nm), which was carried out at an optimum laser focal position, 1 W of laser power and 500 m/s of laser scanning speed. As a result, the problems with the laser patterning method, such as a shoulder at the ITO/glass edge, crack on the surface, and ITO debris were minimized. Moreover, we found that the OLED with laser patterned ITO showed almost similar electrical and optical properties to that of ITO that was patterned by photo-lithography.

PPLN 비선형 결정과 이중통과법을 이용한 DOFA 시스템에서 증폭된 연속발진형 파장가변 적외선 레이저광의 제 2고조파 발생

주기적으로 분극 반전된 비선형 결정 중에 하나인 PPLN(Periodically Poled MgO(5%) doped Lithium Niobate)과 수 W급의 고출력 연속발진형 파장가변 적외선 레이저 시스템인 DOFA(Diode Laser Oscillator & Fiber Amplifier) 시스템을 이용하여, 이 결정에서 펌핑광을 한번 통과시키는 단일통과와 두 번 통과시키는 이중통과에서의 효율적인 제2고조파 발생 조건을 실험적으로 구하였다. 단일통과에서는 최적의 위상정합온도 <TEX>$108.9^{\circ}C$</TEX>에서 최대 출력 2.45 W의 적외선(파장 = 1070 nm) 펌핑광을 사용하여 최대 245 mW의 녹색광원(파장 = 535 nm)인 제 2고조파를 만들었고, 이때의 주파수 변환 효율은 10%였다. 또한 제 2고조파 발생의 효율을 증가시키기 위해서 되 반사용 오목거울과 위상보정을 위한 쐐기유리판을 이용하여 이중통과의 제2고조파 발생장치를 구성하였다. 이때 최적의 위상정합온도 <TEX>$108.5^{\circ}C$</TEX>에서 최대 출력 2.45 W의 적외선(파장 = 1070 nm) 펌핑광을 사용하여 최대 383 mW의 녹색광원(파장 = 535 nm)인 제 2고조파를 만들었다. 이때의 변환 효율은 15.6%로써 단일통과에서의 제 2고조파 발생 효율보다 크게 증가함을 확인하였다. The optimum conditions of second harmonic generation (SHG) can be successfully achieved experimentally using single pass and double pass methods of a pumping beam. The beam has a power of several Watts radiated by a DOFA (Diode Laser Oscillator & Fiber Amplifier) system, which is a high power CW wavelength tunable infrared laser system, in a PPLN (Periodically Poled MgO doped Lithium Niobate) nonlinear crystal. In the case of a single pass method, the parameters are the wavelength of 535 nm for SHG and the output power of 245 mW generated from the pumping input beam with wavelength of 1070 nm and the power of 2.45 W at phase matching temperature of <TEX>$108.9^{\circ}C$</TEX>. The conversion efficiency of SHG was 10%. In order to enhance the output of SHG, the double pass method of the SHG system of a PPLN using a concave mirror for the retroreflection and a pair of wedged flat windows for phase compensation was also presented. In this double pass system, we obtained the SHG output beam with the wavelength of 535 nm and the maximum power of 383 mW at optimum phase matching temperature of <TEX>$108.5^{\circ}C$</TEX> by using an incident pumping beam with wavelength of 1070 nm and the power of 2.45 W. The maximum conversion efficiency is 15.6%, which is more than that of the single pass method.

Integrated IR laser system for micro-fluidic detection and analysis

This paper presents a novel integrated infra-red laser system (λ = 1550 nm) for micro and nano-fluidic investigation and analysis. Its principle of detection is based on attenuated total internal reflection from a diffraction grating, which is for a first time adapted and applied to operate with near infra-red laser source. The sensor is integrated in an autonomous micro-fluidic device and realized by unique fabrication technology. An analysis of aqueous solutions of sucrose is performed by the micro-fluidic chip. The response of the diffraction efficiency of the integrated detector is investigated for the strongest diffraction orders and for different light polarizations. A resolution of the sucrose concentration below 1 wt.% is achieved.

First experiences with a 2.0-μm near infrared laser system for neuroendoscopy

Nd:YAG, argon and diode lasers have been used in neurosurgical procedures including neuroendoscopy. However, many neurosurgeons are reluctant to use these lasers because of their inappropriate wavelength and uncontrollable tissue interaction, which has the potential to cause serious complications. Recently, a 2.0-microm near infrared laser with adequate wavelength and minimal tissue penetration became available. This laser was developed for endoscopic neurosurgical procedures. It is the aim of the study to report the initial experiences with this laser in neuroendoscopic procedures. We have performed 43 laser-assisted neuroendoscopic procedures [multicompartmental congenital, posthaemorrhagic or postinfectious hydrocephalus (n = 17), tumour biopsies (n = 6), rescue of fixed and allocated ventricular catheters (n = 2), endoscopic third ventriculostomy (ETV, n = 17) and aqueductoplasty (n = 1)] in 41 patients aged between 3 months and 80 years. The laser beam was delivered through a 365-microm bare silica fibre introduced through the working channel of a rigid endoscope. It was used for the opening of cysts, perforating the third ventricular floor, and for coagulation prior to and after biopsy. The therapeutic goals [creating unhindered cerebrospinal fluid (CSF) flow between cysts, ventricles and cisterns, sufficient tissue samples for histopathological diagnosis and catheter rescue] were achieved in 40 patients by the first and in 2 patients by a second neuroendoscopic operation. In one child, a CSF shunt was later required despite patency of the created stoma proven by magnetic resonance imaging (MRI). In another patient ETV was abandoned due to a tiny third ventricle. There was neither mortality nor transient or permanent morbidity. The authors conclude that the use of the 2.0-microm near infrared laser enables safe and effective procedures in neuroendoscopy.

Direct Measurement of Interaction Forces Between Islands on Freely Suspended Smectic C Films Using Multiple Optical Tweezers

Smectic liquid crystals can be made to form freely suspended films, two-dimensional systems locally quantized in thickness by an integral number of smectic layers, on which islands, circular regions of greater thickness than the surrounding film area, can be generated. In smectic C films, each such island is accompanied by a topological defect pair, an s = +1 topological defect inside and an s = −1 defect nearby on the background film. The distortions of the in-plane orientational order of the smectic C director field result in elastic interactions between the islands, with a short-range repulsion and a long-range dipolar attraction governing their stability and leading to their organization in chain-like structures with an equilibrium island separation. We demonstrated previously that such islands can be manipulated using optical tweezers. Using an acousto-optically scanned infrared laser system to generate dynamically controllable, multiple optical traps, we have now directly measured the repulsive and attractive elastic interaction forces between smectic C* islands and have compared the results quantitatively with theory. We find that the interactions between islands are much smaller in the racemic smectic C case than in the chiral smectic C*, an effect we attribute to long-range coulombic forces arising from polarization charges.

Soil deformation and its spectral signature

AbstractSpatial variation of the surface micro‐relief in a Sharkey clay soil was investigated. The micro‐relief measurements of the soil surface were obtained using an automated infrared laser system and evaluated with methods of Fourier analysis. The authors illustrate the spectral technique with a simple example and then use the technique to interpret the surface micro‐relief patterns of soil samples subjected to three simulated rainstorm intensities. The periodicity of the soil surface micro‐relief in the longitudinal direction was 80–120 mm. The periodic surface micro‐relief patterns immediately following the rainstorm are shown to be an early manifestation of the cracking pattern. Published in 2006 by John Wiley &amp; Sons, Ltd.

Development of tunable femtosecond infrared laser system and it's applications

Development of tunable femtosecond infrared laser system and it's applications

NIR laser tissue welding of in vitro porcine cornea and sclera tissue

The objective of this study was to test the hypothesis that an near infrared (NIR) laser system (1,455 nm) in combination with a motorized translational stage to control the position and speed of the laser beam and a shutter to control the laser exposure to the tissue being welded could be used to successfully weld ocular tissues. Seventy-five porcine corneas and 23 porcine scleral tissues were welded in vitro in this study. The welded tissues were examined using histopathology and tensile strength analysis. Eight different welding conditions were analyzed for porcine cornea and one for sclera tissues. The tensile strength of the welded groups was compared to a sutured cornea control group. The NIR laser welding system provides strong, full thickness welds and does not require the use of extrinsic dyes, chromophores, or solders. Mean weld strengths of 0.15-0.45 kg/cm(2) were obtained for the cornea and 1.01 kg/cm(2) for sclera welds. The native H(2)O in the ocular tissue serves as an absorber of the 1,455 nm radiation and helps to induce the welds. We conclude that an NIR laser system using an optimal laser radiation wavelength of 1,455 nm can effectively weld cornea and sclera tissue and that this laser tissue welding (LTW) methodology typically causes minimal disruption of tissue, and thus, avoids opacities and irregularities in the tissue which may result in decreased visual acuity. The optimization of a laser welding system that leads to a strong full thickness tissue bond without tissue destruction, an instant seal that promotes wound healing, and the absence of a continued presence of a foreign substance like a suture, is of considerable importance to the ophthalmology medical community. This need is especially apparent with respect to corneal transplantation and fixing the position of corneal flaps in Laser-Assisted In Situ Keratomileusis (LASIK), a laser procedure used to permanently change the shape of the cornea.

An application of tomographic reconstruction of atmospheric CO/sub 2/ over a volcanic site based on open-path ir laser measurements

The southern area of Italy is characterized by the presence of many active volcanic areas. In Pozzuoli (Naples, Italy), an urban area characterized by high volcanic risk, a gas emitting site is present. A high percentage of CO/sub 2/ is emitted, whose atmospheric concentration measurement is an important task in many environmental and scientific applications. In this paper, we describe the utilization over that area of a mobile infrared (IR) laser system, able to measure the CO/sub 2/ concentration along rectilinear atmospheric paths up to 1-km length, and the result of tomographic processing applied to retrieve a two-dimensional CO/sub 2/ concentration field. The laser system computes the link averaged concentration by processing the received IR laser radiation propagated along an open-air rectilinear link connecting the transmitter/receiver laser unit and a passive retroreflector device. A one-day measurement campaign has been made and 15 different atmospheric propagation links were considered moving the transmitter/receiver unit and some retroreflectors.