A K Potemkin

Comparative characteristics of magneto-optical materials

Experimental results of measurements for Russian magneto-optical glasses MOG101, MOG105, MOG04, and MOG10 are presented, including the coefficient of electronic nonlinearity, energy of thermal defocusing, and power resistance. For comparison, the same parameters are shown for the optical glass K8 (an analog of the well-known BK7 glass), the fused silica QU-1, and the laser phosphate glass GLS-22P. The obtained data allow consumers to choose the proper magneto-optical materials for the device operation mode.

Compact 300-J/300-GW Frequency-Doubled Neodymium Glass Laser—Part I: Limiting Power by Self-Focusing

Small-scale self-focusing is the main cause of power limitation in nanosecond Nd:glass lasers. We report pioneer observation in experiment of laser beam noise amplification for B -integral (nonlinear phase) order of unity, i.e., without destruction of nonlinear medium. Analytical dependences of noise amplification coefficient on the B-integral have been obtained for one nonlinear medium as well as for two nonlinear media separated by an air gap with image relay. A simple analytical dependence has been found for an optimal distance between two nonlinear media for which the maximum allowable value of B -integral increases from 2.7 to 4.3. The maximum attainable energy in neodymium-phosphate glass lasers with rod amplifiers 10 cm in diameter is 400 J with a pulse duration of 1 ns.

Spatial filters for high-peak-power multistage laser amplifiers

We describe spatial filters used in a Nd:glass laser with an output pulse energy up to 300 J and a pulse duration of 1 ns. This laser is designed for pumping of a chirped-pulse optical parametric amplifier. We present data required to choose the shape and diameter of a spatial filter lens, taking into account aberrations caused by spherical surfaces. Calculation of the optimal pinhole diameter is presented. Design features of the spatial filters and the procedure of their alignment are discussed in detail.

Compensating for birefringence in active elements of solid-state lasers: novel method

It is shown that a uniaxial crystal (cut along the optical axis) placed inside a telescope may compensate for thermally induced birefringence in laser-active elements. Depolarization was reduced in an experiment by an order of magnitude.

Disk Yb:KGW amplifier of profiled pulses of laser driver for electron photoinjector.

We investigated a diode-pumped multipass disk Yb:KGW amplifier intended for amplifying a train of 3D ellipsoidal pulses of a laser driver for a photocathode of a linear electron accelerator. The multipass amplification geometry permitted increasing the energy of broadband (about 10 nm) pulses with a repetition rate of 1 MHz from 0.12 µJ to 39 µJ, despite large losses (two orders of magnitude) introduced by a beam shaper of 3D ellipsoidal beam. The distortions of the pulse train envelope were minimal due to optimal delay between the moment of pump switching on and arrival of the first pulse of the train.

Shaping of cylindrical and 3D ellipsoidal beams for electron photoinjector laser drivers.

With the use of spatial light modulators it became possible to implement in experiments the method of controlling the space-time intensity distribution of femtosecond laser pulses stretched to picosecond duration. Cylindrical and quasi-ellipsoidal intensity distributions were obtained and characterized by means of a 2D spectrograph and a cross-correlator.

Computer-aided two-coordinate autocollimator for measuring small angular deviations

A computer-aided autocollimator for measuring small angular deviations is described. Small angular displacements are determined by the displacement of the laser beam image on a CCD array in the focal plane of a lens. Automatic control of the displacement systems allows one to test many times the systems of precision remote displacement of optical components with a minimum detectable angular deviations of about 0.2″.

Reduction of Self-Focusing in Solid State Lasers

We report pioneer observation of small scale self-focusing at B-integral less than unity. An analytical dependence has been found for distance between two laser rods, for which maximum allowable B-integral increases from 2.7 to 4.3.