O. A. Orlov

New Laser For Interferometry With Long-Term Frequency Stabilization At 1.06 μm Onto Molecular Cesium Standard

The single-frequency cw YAG:Nd laser with frequency stabilization onto spectroscopic standard at 1.06 μm - molecular cesium absorption lines - is described. It is shown, that the spectrum of saturated absorption of Cs2 gives for this spectral range the optical scale of reference frequencies, which is convenient for the utilization in interferometric systems and in the heterodyne systems in particular. Spectroscopic properties of this cesium reference are presented. The heterodyne measurements of Allan variance in the experiments with two independent frequency stabilized YAG:Nd lasers which gave the highest value of relative frequency stability at a level of 6x10-11 are described.

Self-stabilization of a continuous wave multimode green laser due to antiphase dynamics

The stability of a diode pumped Nd:YAG laser with intracavity KTP in an L-shaped cavity is studied. The mirror which connects the two cavity arms is a dielectric which also acts as a partial polarizer. This design provides a high level of stability for the total output power, despite the instability of the separate modes: separate modes are chaotic with large amplitude noise while the total output displays reduced noise below 1% rms. A model based on the Jones matrices is studied numerically. It shows antiphase and clustering, in excellent qualitative agreement with the experimental data.

Ultrasensitive Intracavity Technique Of Optical Measurements And Interferometric Detection Of Linear Movements With The Sensitivity 10-16m/√Hz

Ultrasensitive interferometer measurement technique using laser response to cavity loss modulation is described. The advantages and possibilities of this method are analyzed. The model of laser displacement sensor based on cw stabilized YAG:Nd laser with intracavit.v Michelson interferometer has been built and tested.The sensitivity of 10-16 m/√Hz has been achieved in the frequency range above 40 kHz, which is close to theoretical limit determined by natural laser amplitude noise.

Mode-locking in intracavity frequency doubled Nd:YVO4 laser

We experimentally study passive mode-locking in Nd:YVO4 laser based on second harmonic generation in KTP crystal. We characterized RF spectra and optical spectra versus pump power, the KTP crystal temperature and position, the output coupler reflectivity, and the intracavity polarizer. We discuss the device performance considering cascaded χ(2) lensing in KTP, frequency doubling nonlinearity, and Kerr lens formed in Nd:YVO4. Implementing an intracavity Lyot filter and cavity length modulation via PZT does not affect mode-locking capability. These results and ultra-low noise mode beat signal open a new perspective for stable RF signal generation by transferring optical reference stability (iodine absorption lines) into RF domain.

A RF standard based on a longitudinal modes beat note of a frequency locked laser

We demonstrate a new approach to designing a compact RF standard based on longitudinal mode beating. We use frequency doubled Nd:YVO4 laser operating in mode-locked regime stabilized to hyperfine transitions in molecular iodine. A similar system is used for estimating the standard Allan deviation of RF signal which is 2.1 × 10-14 at the time 100 s.

A new RF frequency standard design based on a beat note between longitudinal modes of a frequency locked CW-laser

We demonstrate a new approach to designing a compact RF standard based on the transfer of frequency stability of hyperfine transitions in molecular iodine to the stability of a laser cavity length. We use frequency doubled Nd:YVO4 laser operating in Kerr lens mode-locked regime and frequency lock it to hyperfine transitions in molecular iodine with further detecting the beat note signal between longitudinal modes on a fast photodiode. A similar system is used for estimating the standard Allan deviation of RF signal which is 2.1 x 10-14 at the time 100 s.

Population of higher-energy levels in LiY1-xErxF4(x=0.003/1) crystals under CW IR laser-diode pumping

Steady-state population of 7 lowest excited erbium levels in LiY1-xErxF4 (YLF:Er3+) crystals was studied under up conversion CW InGaAs laser-diode pumping with varied power density. Theoretical and experimental concentration and power dependencies of population of higher-energy radiative levels were obtained. Relative changes in populations of studied levels in YLF:Er3+ crystals were experimentally controlled by visible spectra of steady-state luminescence in the wavelength ranges corresponding to transitions 4S3/2 yields 4I15/2 micrometers and 4F9/2 yields 4I15/2 micrometers . IR-pumped luminescence kinetic curves of higher-energy transitions 4S3/2 yields 4I15/2 and 2H9/2 yields 4I15/2 were recorded. The energy-transfer mechanisms were determined, and the predominant mechanisms responsible for up conversion excitation were elucidated. Microparameters of energy transfer and concentration dependencies of the self-quenching rates and non-linear coupling were obtained on the basis of theoretical and experimental estimates of the rates of intra- and intercenter relaxation processes allowing for statistics of coupling between the impurity centers in the system. The steady-state dependencies of population on the erbium concentration and pumping power density were calculated within the framework of rate balance equations. Good agreement between the theory and experimetnal data was obtained.

High-average-power double-waveguide slab laser for material processing

Novel principles of design of a diode-pumped solid-state laser with scalable average output power are described. The approach is based on a double waveguide slab (DWS) concept, when laser slab has a waveguide equality both for pump and laser radiation propagation in the orthogonal directions. The advantages of such a scheme are efficient conduction- cooling and scalability of a laser head to the kW range with the high quality of a laser beam. The feasibility of this concept was proved with the model of a DWS Nd:YAG laser at the level of average output power of 10W. The promising possibility to use thermally strengthened Nd-glass for a high average power qcw laser is discussed.