K.A. Stankov

Two-wavelength single mode grazing incidence dye laser

Abstract Two-wavelength single mode operation of a N2-laser pumped dye laser is described. The proper choice of a grazing incidence grating and highly selective cavity elements provided a stable operation of the laser. A single mode spectrum of 310 ± 50 MHz is measured and both wavelengths are independently tunable over the entire gain profile of the R6G DN dye.

Frequency-domain analysis of the mode-locking process in a laser with a second-harmonic nonlinear mirror

We present a computer simulation of the mode-locking process in a pulsed Nd:YAG laser with a nonlinear mirror based on second-harmonic generation. For the first time to our knowledge, a frequency-domain description of the passive mode-locking process is presented, which provides complete information for the amplitude and phase evolution of the individual modes. The mode locking is described as being due to the interaction of the longitudinal modes in the nonlinear mirror through second-harmonic and sum- and difference-frequency generation.

Compensation of group-velocity mismatch in the frequency-doubling modelocker

We propose a method for reducing the deteriorating effect of group-velocity mismatch on the frequency-doubling modelocker time response. A birefringent plate is used to introduce a time delay between the fundamental and the second-harmonic pulses which is opposite in sign to that accumulated in the frequency-doubling crystal. In the new arrangement the modelocker may provide pulse compression at a sub-picosecond time scale

Frequency-doubling mode locker : the influence of group-velocity mismatch

The influence of the group-velocity mismatch between the fundamental and the second harmonic in the frequency-doubling nonlinear mirror is investigated theoretically. The nonstationary analysis provides an estimation for the maximum pulse-shortening capabilities of the device when it is used as a passive mode locker. The pulse-shape deformation is also investigated.

Pulse shortening in an actively mode-locked laser with a frequency-doubling nonlinear mirror

Abstract A significant shortening of the output pulse duration in an actively mode-locked laser was observed when one of the laser mirror was replaced with a nonlinear mirror, based on second harmonic generation. The kinetics of the intracavity pulse compression was investigated in lasers with Nd:YAG and Nd:KGd(WO 4 ) 2 rods. Pulse shortening as much as 4–6 times in comparison with purely active mode-locking, was measured.

Intense laser generation from an atomic-fluorine laser

An intensive generation of radiation from a discharge-pumped atomic-fluorine gas laser is reported. A peak power exceeding 330 kW and a total energy of more than 2 mJ is obtained for a number of lines in the red, using a NF3∶He (1∶100) gas mixture at total pressure of 500 Torr. The circuitry optimization is described and the conditions for effective operation of the atomic-fluorine laser are discussed. The temporal and the spectral characteristics of the laser emission are also presented.

A novel double grazing-incidence single-mode dye laser

Using only one grating and plane parallel glass plate in a novel double-grazing incidence configuration, twice higher dispersion is obtained, resulting in twofold narrowing of the single-pass linewidth, compared to the single grazing-incidence scheme. This laser cavity design features several-times improved signal-to-noise ratio and enhanced stability. Single-mode operation of 210±50 MHz is demonstrated.

Mode locking of a Nd:YAlO 3 laser at the 1.34-μm transition by a second-harmonic nonlinear mirror

A second-harmonic nonlinear mirror formed by a LiIO(3) frequency doubler and a dichroic output mirror is employed to mode lock the 1.34-microm transition of a pulsed Nd:YAlO(3) laser. Pulses of 15-ps duration are reliably generated simultaneously at 1.34 and 0.67 microm.

Extremely long train of ultra short pulses from an actively mode-locked pulsed Nd: YAG laser

Abstract An actively mode-locked pulsed Nd:YAG laser with passive feedback control was used to obtain millisecond trains of ultra-short light pulses. The intracavity second harmonic generation in a crystal situated at a proper distance from the output mirror served as a negative feedback. The length of the train was limited by the length of the flash lamp pumping pulse.

Mode locking of a Nd:YAlO/sub 3/ laser at 1.08 and 1.34 mu m wavelengths using a single LiIO/sub 3/ crystal

Passive mode locking of a Nd:YAlO/sub 3/ laser at 1.08 and 1.34 mu m using a nonlinear mirror based on second harmonic generation is described. A single 30 degrees cut frequency-doubling LiIO/sub 3/ crystal was used to mode lock both transitions, demonstrating the superiority of this mode-locking technique over that using saturable absorbers. Pulses as short as 50 ps at 1.08 mu m and 15 ps at 1.34 mu m were obtained. A comparative analysis of the mode-locking performance at the two fundamental wavelengths is presented, indicating that the longer pulse duration at 1.08 mu m is due to the higher gain and an insufficient number of round-trips in the pulse train development. >