An efficient,RF excited,waveguide CO2 laser

A CW waveguide CO₂ laser excited by a transverse radiofrequency discharge is described. An efficiency of 8.5% (laser power/RF power from supply) has been achieved and an output power of up to 4.6 W.     

High power repetitive TEA CO2 pulsed laser

A high power repetitive spark-pin UV-preionized TEA CO₂ laser system is presented. The discharge for generating laser pulses is controlled by a rotary spark switch and a high voltage pulsed trigger. Uniform glow discharge between two symmetrical Chang-electrodes is realized by using an auto-inversion circuit. A couple of high power axial-flow fans with the maximum wind speed of 80 m/s are used for gas exchange between the electrodes. At a repetitive operation, the maximum average output laser power of 10.4 kW 10.6 ??m laser is obtained at 300 Hz, with an electro-optical conversion efficiency of 15.6%. At single pulsed operation, more pumping energy and higher gases pressures can be injected, and the maximum output laser energy of 53 J is achieved.     

Design and operation characteristics of a high power transverse flow pulser sustained cw CO2 laser

A transverse flow, transverse discharge cw CO₂ laser in which de discharge is sustained by employing high repetition rate high voltage pulses has been developed. Pulser sustained discharge through electrodes of innovative design provided uniform excitation at electrical input power densities more than 10 W/cc. Laser output power more than 2.5 kW was obtained in a laser gas mixture consisting of 0.5 mbar of CO₂, 16 mbar of N₂ and 38.5 mbar of He. Design details and operational characteristics of this laser are presented.     

Fast-axial-flow CO2-laser with integrated turbo-blower

A new type of CO₂-laser with high-power capability is described. It employs fast axial flow driven by a high-frequency radial impeller. Due to the coaxial design which integrates discharge tube, blower, and gas cooler into a single cylindrical housing, a very compact laser unit is realized. The discharge is rf excited (13.56 MHz). With a specific input power of 21 W/cm³ an output of 800 W is generated at an efficiency of 16%. The discharge can easily be operated in a pulsed mode with frequencies up to 10 kHz.     

A 15.1 W continuous wave TEM00 mode laser using a YVO4/Nd:YVO4 composite crystal

A effective continuous-wave (CW), high power laser generated using a YVO₄/Nd:YVO₄ composite crystal is presented. 18.8 W output power in multi-mode has been achieved with a maximum absorbed pump power of 31.2 W, corresponding to an optical-to-optical efficiency of 60.26%. In TEM₀₀ mode operation, 15.1 W output power also has been achieved with the maximum absorbed pump power of 31.2 W, corresponding to an optical-to-optical efficiency of 47.69%. With a 200 mm focal-length positive lens and using the moving knife-edge method, the beam quality factor is measured to be M² = 1.2 for TEM₀₀ mode beam.     

Design and experimental characterisation of a DC-excited CW/repetitively pulsed sealed off CO2 laser

This paper reports the design procedure and experimental study of a sealed off CO₂ laser. Simple algorithms for threshold and steady state excitation voltage calculation, resonator design and its temperature dependent operation are presented. The sealed off CO₂ laser was operated both in CW and pulsed modes and found stable both thermodynamically and optically. Frequency limits for pulsed operation regarding maximum and minimum output energy ranges are determined. Different aspects of CO₂ laser studied include threshold excitation voltages, temperature dependent efficiency, optical power saturation limitations, pulsed and steady state discharge currents for optimum gases mixture combinations. The laser has successfully been constructed, operated and tested for different applications within the limits of its maximum output power of 14 W.     

Diodes-double-end-pumped high efficiency continuous wave 36 W TEM00 mode Nd:GdVO4 laser

A effective continuous-wave (CW), high power laser generated using a YVO₄/Nd:YVO₄ composite crystal is presented. 18.8 W output power in multi-mode has been achieved with a maximum absorbed pump power of 31.2 W, corresponding to an optical-to-optical efficiency of 60.26%. In TEM₀₀ mode operation, 15.1 W output power also has been achieved with the maximum absorbed pump power of 31.2 W, corresponding to an optical-to-optical efficiency of 47.69%. With a 200 mm focal-length positive lens and using the moving knife-edge method, the beam quality factor is measured to be M² = 1.2 for TEM₀₀ mode beam.     

Construction of a photon drag detector for evaluating the performance of a CO2 laser amplifier

In this article, the construction of P-type germanium (Ge) photon drag detector which is used to characterize the gain and output powers of a 10 W CO₂ laser and a CO₂ laser amplifier is described. Gain and laser amplifier output power versus laser input power measurements collected at 4.7 mbar and 12.0 mbar amplifier tube pressures are discussed. Moreover, measurements relating the CO₂ laser output power to the laser tube discharge current are provided at 6.9 mbar and 7.3 mbar tube pressures.     

AC-chopper application for CW CO2 laser

A microprocessor-based algorithm was developed to control the power supply to a CO₂ laser using an AC-chopper method. This system was connected directly to a CO₂ laser tube without the need for a dc-dc converter or the storage capacitance of a multilevel circuit. The typical CO₂ laser power supply system had a full-bridge series resonant inverter or voltage multiplier. AC-to-AC converter schemes using zero voltage switching (ZVS) can be used efficiently and economically for low and medium power applications.This paper reports the performance characteristics of a symmetrical AC-chopper technology that can maintain the quality of the ac output of a CO₂ laser tube, regardless of the amount of switching loss. The laser was operated to an output power, maximum system efficiency total gas mixture of 37.2 W, 92%, and CO₂:N₂:He=1:9:15, respectively. The laser system, AC-chopper power supply and its operation were examined.     

A DC excited waveguide multibeam CO2 laser using high frequency pre-ionization technique

High power industrial multibeam CO₂ lasers consist of a large number of closely packed parallel glass discharge tubes sharing a common plane parallel resonator. Every discharge tube forms an independent resonator. When discharge tubes of smaller diameter are used and the Fresnel numberN ≪ 1 for all resonators, they operate in waveguide mode. Waveguide modes have excellent discrimination of higher order modes. A DC excited waveguide multibeam CO₂ laser is reported having six glass discharge tubes. Simultaneous excitation of DC discharge in all sections is achieved by producing pre-ionization using an auxiliary high frequency pulsed discharge along with its other advantages. Maximum 170 W output power is obtained with all beams operating in EH₁₁ waveguide mode. The specific power of 28 W/m is much higher as compared to similar AC excited waveguide multibeam CO₂ lasers. Theoretical analysis shows that all resonators of this laser will support only EH₁₁ mode. This laser is successfully used for woodcutting     

Diode-pumped high-efficiency passively Q-switched Yb:CaYAlO<Subscript>4</Subscript> laser

We experimentally demonstrated a high-efficiency passively Q-switched Yb:CaYAlO₄ (Yb:CYA) laser based on a semiconductor-saturable absorber mirror (SESAM), and the output characteristics of the laser including the average output power, repetition frequency, pulse duration, pulse energy and pulse peak power were investigated by adopting output mirrors with different transmittances. When the transmittance of the output mirror was 5% and the pump power was set at about 7.76 W, a maximum average output power of as high as 2.480 W was achieved with a slope efficiency and light-to-light efficiency of the Q-switched Yb:CYA laser of up to 37.1% and 31.2%, respectively.     

New cw far-infrared D2O, 12CH3F and 14NH3 laser lines

The operation of a continuous CO₂ waveguide laser at nearly atmospheric pressure is reported. A plasma injection technique is used to produce a uniform discharge at atmospheric pressure. Continuous output power of 0.6 W was obtained at the inlet pressure of 800 torr. Corresponding outlet pressure was 340 torr. While the maximum output power was 1.4 W at the inlet pressure of 600 torr. The gas mix ratio was CO₂ : N₂ : He = 1 : 1 : 6.     

Optimization of gas pressures ratio in a fast-axial-flow CO2 laser with genetic algorithm

In this paper, the laser output power of a fast-axial flow CO₂ laser was optimized with gas pressures ratio of CO₂:N₂:He using a genetic algorithm technique. The power of laser was increased from 500 W (un-optimized case) to 2200 W (simulated case), also experimentally the power has achieved the value of 700 W (optimized case).     

印刷电路板预电离3.6 kW TEA CO2激光器

在TEA CO₂激光器中采用印刷电路板预电离结构,在单节放电体积为5cm×4cm×90cm 的两节串连的激光器中获得了20.4 J单脉冲能量输出,电光转换效率达12.8％.激光器重复频率工作时,气体清洗系数大于3,在最高重复频率180 Hz下获得了3.6 kW平均输出功率.     

Laser diode and pumped Cr:Yag passively Q-switched yellow-green laser at 543 nm

Efficient and compact yellow green pulsed laser output at 543 nm is generated by frequency doubling of a passively Q-switched end diode-pumped Nd:YVO₄ laser at 1086 nm under the condition of sup-pressing the higher gain transition near 1064 nm. With 15 W of diode pump power and the frequency doubling crystal LBO, as high as 1.58 W output power at 543 nm is achieved. The optical to optical conversion efficiency from the corresponding Q-switched fundamental output to the yellow green output is 49%. The peak power of the Q-switched yellow green pulse laser is up to 30 kW with 5 ns pulse duration. The output power stability over 8 hours is better than 2.56% at the maximum output power. To the best of our knowledge, this is the highest watt-level laser at 543 nm generated by frequency doubling of a passively Q-switched end diode pumped Nd:YVO₄ laser at 1086 nm.     

Interaction of tea CO2 laser light with plasma

High power double discharge type TEA CO₂ laser was used to study laser plasma interaction on carbon target plasma. The maximum output power was 0.3 GW and full width at half maximum intensity was 100 ns. We measured the reflectivity of the laser light at 10.6 μm in wavelength from the carbon plasma. The reflectivity showed a maximum (≈56%) at the laser power intensity of about 1.1 x 10¹⁰ W/cm², and at above this value, the reflectivity decreased. The absorption was introduced effectively above this intensity. The electron density and temperature were also measured.     

X-ray preionized CO2 laser

A short pulse (100 ns) high-energy x-ray source has been used to preionize a transversely excited carbon dioxide gas discharge laser of 600 cm³ active volume. The maximum output power of 60 MW in a 50 ns FWHM pulse was achieved from a CO₂–N₂–He–CO–Xe static gas mixture at 600 Torr pressure. The energy conversion efficiency was 6%.     

Resonantly-pumped Er3+:Y2O3 ceramic laser for remote CO2 monitoring

Laser performance of resonantly-pumped Er³⁺-doped Y₂O₃ ceramic laser for remote DIAL CO₂ monitoring is reported. Slope efficiency of 64.6% and output power of over 9.3 W have been achieved with this eyesafe, 1.6-μm, CW laser in a cryogenically cooled operation regime despite the marginal optical quality of currently available laser gain material.     

钙原子与离子共振-亚稳跃迁激光的同时振荡

在电极间距为46cm、内径为1.3cm的石英放电管中,通过高频纵向脉冲放电激励,获得波长为0.85μm/0.87μm和5.54μm的钙离子和原子共振-亚稳跃迁激光的同时振荡.最大激光总功率和效率分别达1.1W和0.1%.测量并分析了激光输出特性和各工作参量之间的关系.     

激光二极管双端直接抽运混合腔板条激光器

为减少热透镜效应的影响, 获得高光束质量的激光, 本文利用激光二极管阵列双端直接抽运Nd:YVO₄, 采用负支共焦折叠混合腔结构, 获得最高功率为416 W 1064 nm的激光输出, 光–光转换效率为54.3%, 斜效率为61.6%. 在输出功率为370 W时, 光束质量因子M²在非稳腔和稳腔方向上分别为3.9和4.7.