Yongyuan Song

High-performance self-pumped phase conjugator with a multichannel in KNSBN:Cu crystal

A Cu-doped (0.04 wt. %) (K(0.5)Na(0.5))(0.2)(Sr(0.61) Ba(0.39))(0.9)Nb(2)O(6) crystal produced as much as 68% self-pumped phaseconjugate reflectivity at the laser wavelength lambda = 514.5 nm. We also observed some phenomena that helped us to understand the mechanism for the self-pumped phase-conjugate mirror.

Growth and properties of a new TB type photorefractive crystal

This paper is focused on the studies on the new composition of tungsten bronze photorefractive KNSBN:Cu crystals. By changing the A-site occupation of the crystals and doping Cu ions in them, their ferroelectric and photorefractive properties were modified. These new crystals have excellent polarization stabilities and a two-wave coupling gain coefficient as large as 20 cm −1 . The photorefractive sensitivity is of the order of 10 −3 cm 2 /J and the cat-SPPC reflectivity can reach 65% with a response time lower than 10 s.

Studies on self-pumped phase conjugation in Cu-doped (K0.5Na0.5)0.2(Sr0.61Ba0.39)0.9Nb2O6 crystals

The use of Cu-doped (K0.5Na0.5)0.2(Sr0.61Ba0.39)0.9Nb2O6 as self-pumped phase conjugators using internal reflection is reported. Reflectivities as high as 63% at 5145.5 nm and 60% at 632.8 nm were realized. It was found that the photorefractive response changes significantly at different doping concentration. The responses of the crystals to the laser wavelength, incident angle and dopant concentration are studied.

Contradirectional two-wave mixing in a strontium barium niobate self-pumped phase-conjugate mirror.

Contradirectional two-wave mixing in the process of self-pumped phase conjugation is analyzed theoretically, and it is found that this coupling interaction can enhance or restrain the phase-conjugate reflectivity depending on the optical configuration. This analysis is used to explain the unusual experimental results that were obtained in a strontium barium niobate self-pumped phase conjugator.

Enhanced self-pumped phase conjugation from 16°-cut KNSBN:Cu

With the maximum coupling coefficient and high internal reflection conditions, the self-pumped phase-conjugation reflectivity of copper-doped potassium sodium strontium barium niobate (KNSBN:Cu) is increased with 16 degrees -cut samples. The response time is also shortened. The resolution property of 16 degrees -cut KNSBN:Cu is determined and a distorted image is corrected by using the 16 degrees -cut sample.

Demonstration of self-pumped phase conjugation with laser beam incident to strontium barium niobate crystals from a negative c face

The self-pumped phase conjugation in strontium barium niobate (SBN) crystal is demonstrated by causing the laser beam to enter into the crystal from negative c face. Comparison is made between the experimental results and those obtained by the conventional configuration. The analysis and discussion are also presented.

Studies of the formation of self-pumped phase conjugation in a Cu-doped KNSBN crystal

Abstract The internal self-generated loop in a photorefractive Cu-doped KNSBN crystal and the nehavior of phase-conjugate beams during self-pumping have been studied experimentally. Their relations to the crystals coupling constant, dimension and experimental conditions were analyzed.

Studies of a ring phase-conjugate mirror containing a photorefractive crystal with asymmetric transmission

The characteristics of the ring passive phase conjugator with a nonreciprocal transmission photorefractive crystal inside its loop are studied experimentally and theoretically. It is found that the orientation of the photorefractive crystal and the ratio of energy losses in the two sides of the crystal within the loop can combine to influence the phase-conjugate reflectivity of this device.

Photorefractive-crystal shape-parameter influence on formation of self-pumped phase conjugation

The influence of crystal-shape parameters on formation of self-pumped phase conjugation is studied experimentally. The parallelism of two c-cut faces of a barium strontium potassium niobate crystal of cuboid shape is changed to control the internal oscillation and thus to induce or to suppress the generation of self-pumped phase conjugation.

Theoretical investigation of photorefractive ring passive phase-conjugate mirror in the presence of asymmetric transmission

Abstract The performance of a photorefractive ring phase-conjugate mirror is found to be determined by the combined effect of coupling the strength (ΓL), the product (T 1 T 2) and the ratio (T 1/T 2) of the cavity transmissivities along the two directions. The threshold phase-conjugate reflectivity of the device can be changed or controlled by the variation of these three parameters.