Transverse Diode Pumping Research Articles

Two-level gas laser with transverse diode pumping

We theoretically study a new method for generating laser radiation by a two-level system without population inversion in the ‘red’ wing of its spectral line under resonant absorption of broadband radiation from pump laser diodes. A two-level system simulates the atoms of an active gas in an atmosphere of a high-pressure buffer gas. The effect results from the fact that in the ‘red’ wing of the spectral line, the probability of stimulated emission exceeds the probability of absorption if the homogeneous broadening due to the interaction of particles with the buffer gas significantly exceeds the natural one (at high pressures of the buffer gas). Analytical formulae are obtained that describe the operation of a two-level gas laser with transverse diode pumping. It is found that the longer the active medium, the higher the buffer gas pressure and pump radiation intensity, and the smaller the width of the pump radiation spectrum, the greater the efficiency of conversion of pump radiation into laser radiation. In a sufficiently long active medium (the length of the medium is 50 times its width), the conversion efficiency can reach 44 % at a buffer gas pressure of 5 atm, a pump diode radiation intensity of 3 kW cm−2, and a half-width of its spectrum of 1 cm−1. A two-level gas laser with transverse diode pumping is capable of generating continuous optical radiation with a very high (up to 100 kW) power. The frequency of laser radiation can be tuned by several tens of cm−1.

Monopulse Lasers Based on Yttrium Aluminum Garnet with Neodynium Ion with Resonators Based on an Optical Circuit of a Four-Pass Amplifier with Transverse Diode Pumping

Monopulse Lasers Based on Yttrium Aluminum Garnet with Neodynium Ion with Resonators Based on an Optical Circuit of a Four-Pass Amplifier with Transverse Diode Pumping

Possibility of inversionless amplification and generation of radiation by a two-level system in the ‘red’ wing of its spectral line under resonant diode pumping

We report a theoretical study on the possibility of amplification and generation of radiation by an inversionless two-level system in the ‘red’ wing of its spectral line under resonant diode pumping. The two-level system is used to simulate atoms of an active gas, while it is in the atmosphere of a high-pressure buffer gas. The effect results from the fact that the probability of stimulated emission in the ‘red’ wing of the spectral line exceeds the probability of absorption if the homogeneous broadening due to the interaction of particles with the buffer gas significantly exceeds the natural one (at high pressures of the buffer gas). It is found that the higher the buffer gas pressure and the higher the pump radiation intensity, the greater the inversionless amplification. It is shown that the gain in a two-level system in the ‘red’ wing of its spectral line can reach 0.011 cm−1 when the radiation intensity and the width of the radiation spectrum of pump diodes are 5 kW cm−2 and 4 cm−1, respectively. The use of transverse diode pumping of an active medium placed in an optical cavity will make it possible to obtain lasing with frequency tuning and thereby solve the problem of converting incoherent broadband radiation into a coherent laser light in a gas of two-level active particles.

Single-mode Nd:YAG laser with transverse diode pumping and multiloop self-pumped phase-conjugate cavity

A high-power compact repetitively pulsed Nd:YAG laser with transverse diode pumping and multiloop self-pumped phase-conjugate cavity is proposed. Pulse trains with an energy of 1.5 J and beam quality parameter of M 2 ≤ 1.2 are generated at a divergence of 0.4 mrad and luminance of 5 × 1014 W/(cm2 sr). The peak power of single-frequency pulses is greater than 15 MW at an energy of 170 mJ and a laser bandwidth of 300 MHz.

Compact transversely diode-pumped Nd :YAG laser with a self-pumped phase-conjugate multiloop cavity

A compact high-power repetitively pulsed Nd :YAG laser with transverse diode pumping and a multiloop self-pumped phase-conjugate cavity is presented. The obtained pulse trains have an energy of with beam quality , a divergence of , and a spatial brightness of . The peak power of single-frequency pulses exceeds at a pulse energy of . The laser bandwidth is .

Transversely diode-pumped -switched Nd : YAG laser with injection of radiation from a single-frequency semiconductor laser

A -switched Nd : YAG laser with a high-power transverse diode pumping and injection of seed radiation generated by a single-frequency semiconductor laser is described. The threshold seed radiation power at which the -switched Nd : YAG switches to the single-frequency mode is (radiation intensity . With increasing injection power, the spectral and power characteristics of the -switched laser almost do not change at a constant excitation of its active medium. The spectral linewidth of the -switched Nd : YAG laser with injection from a TLD-1060-14BF single-frequency semiconductor laser module does not exceed (wavelength .

SIMULATION OF LASER TRANSMITTER BASED ON ND: YAG WITH PASSIVE COOLING FOR RANGEFINDING

Laser emitters used in rangefinders without cooling have several limitations: low energy, high beam divergence at the cavity exit that leads to large output telescope design that significantly increases rangefinder’s size, long time beam parameters instability due to laser crystal heating. In the article laser emitter for a transmitting unit of rangefinder based on cylindrical laser medium Nd:YAG with transverse diode pumping abled to solve all the abovementioned promblems is considered. Matrix optics and balance equations were used for system modeling. The emitter is based on plano-concave scheme cavity with internal concave lens aimed for matching the size of TEM00 mode with the size of laser medium and cavity tuning to stability threshold which allows to achieve divergence of the output pulse at diffraction level for 5 mm diameter medium and 300 mm cavity length. Cavity reconfiguration and mode size compliance is conducted by the longitudinal movement of lens relative to the rear mirror. Three-, twoand one-sided pump schemes are compared in terms of rod energy absorption uniformity and their effectiveness. The three-sided pump scheme model with a system of gold coated reflectors was designed that provides 54 % efficiency of pump when the pump energy is distributed uniformly along the cross-section of the laser medium. Based on the modeling in ANSYS the scheme of laser medium thermal control in vacuum conditions was suggested that implies introduction heat-conducting glue between the side edge of a laser medium and quantron body that allows to low the active medium heating in the 8 min cycle by 35 °С. Beam pulse energy under pump of 1.2 Joule equals to about 0.3 Joule with the 4 ns pulse time and 2 Hz in frequency.

Peculiarities of Forming Single-Frequency Generation in a Monopulse YAG:Nd-Laser with Transverse Diode Pumping and Injection of Narrow-Band Radiation

The features of forming output radiation in a powerful monopulse single-frequency side diode-pumped laser operating in external narrow-band signal seeding mode were investigated. The monopulse single-frequency laser was fabricated of a YAG:Nd active element excited by three laser diode matrices. A compact continuous-wave YAG:Nd-laser with longitudinal diode pumping served as the seeding laser. It was shown experimentally that the transition of the monopulse laser from multimode to single-frequency lasing with a spectral line width of about 54 MHz (0.2 pm) occurs at seeding-laser radiation power P th ≈ 0.14 mW (radiation intensity of 1.8·10–2 W/cm2). Increasing the seeding-laser power over P th does not lead to a noticeable change of the output characteristics of the monopulse laser for a given pump level (above the threshold). If the pump power varies from 1.5 to 3.0 kW, the P th value is not changed but the energy of the output pulses of single-frequency monopulse generation increases to 40 MJ. The low level of the external narrow-band seeding signal allows us to consider the single-frequency low-power semiconductor laser as a promising source of the seeding signal.

A method for controlling the phase locking of a multichannel laser system

The conditions leading to control over phase-locked oscillation in a set of three loop lasers containing self-pumped phase-conjugate gain-grating mirrors by using a LiF: F2− passive Q-switch are studied both experimentally and theoretically. Cases of spatially uniform lamp pumping and high-efficiency spatially nonuniform transverse diode pumping are considered.

Powerful solid-state transversely diode-pumped YAG: Nd lasers with improved radiation quality

YAG: Nd lasers with transverse diode pumping of a cylindrical active (lasing) element are developed and studied. Pumping is carried out with continuous-wave (cw) laser diode array modules. At pump powers of 500, 820, and 1400 W, the output powers of the lasers operating in the multimodal regime are, respectively, 150, 350, and 500 W. The optical efficiency exceeds 30%. In the case of an unstable resonator operating in the negative branch of the stability diagram, the laser power equals 320 W with a beam divergence only twice as large as the diffraction limit. The design of a YAG: Nd laser pumped with pulsed-periodic laser diode array modules is presented. The total pump energy is 5 J, and the width and repetition rate of pulses are, respectively, 250 μs and 100 Hz.

Erbium-glass slab laser with transverse diode pumping

A slab laser based on borosilicate phosphate glass doped with erbium and ytterbium with transverse diode pumping has been developed and investigated. In the passive Q-switching regime, using a shutter based on a glass-crystalline material with nanosize spinel doped with divalent cobalt ions, the energy of the output radiation was 1.3mJ with a pulse width of 19ns. With active Q switching, the energy of the developed laser was 2.3mJ. The internal optical losses are estimated, and the parameters of the passive shutter are determined.

Spatial and polarization properties of the output beam of an ytterbium-erbium laser with transverse diode pumping

The propagation parameter M2 of the beam of an ytterbium-erbium glass laser with transverse diode pumping has been experimentally investigated for various cavity configurations. The polarization characteristics of the laser radiation are presented for cases in which the active medium is excited by two and four linear laser-diode arrays.

Study of the thermal lens in a 150-W solid-state processing laser with semiconductor pumping

This paper discusses how the focal power of the thermal lens that appears in the active element of a YAG:Nd laser with transverse pumping by thirty linear laser-diode arrays having a total optical power of up to 600 W depends on the pump power and the temperature of the laser diodes. The optimum working temperature as a function of the diode current is determined. The power balance during diode pumping is considered, and the contributions of various mechanisms to the thermal processes in the crystal of the active element are determined. A practical technique is described for calculating thermal lenses in solid-state lasers with transverse diode pumping. © 2003 Optical Society of America

Neodymium-doped yttrium aluminum garnet laser with transverse diode pumping and a system for cooling the active element with thermoelectric modules

This paper proposes an illuminator for a laser-diode pumping system that includes a plate–focon system and counter-reflectors, as well as a way to cool the active element of a solid-state neodymium-doped yttrium aluminum garnet laser by means of thermoelectric modules based on the Peltier effect. Results are given of a study of the given laser, operating in the pulsed, pulsed-periodic, and continuous modes. In a flat cavity with backstop and half-silvered output mirrors, a radiation power of 2.5 W can be attained in the beam in the continuous regime.