Tang Jun-xiong

Experimental study of a model digital space optical communication system with new quantum devices

We report a digital space optical communication system with new features both in the transmitting and in the receiving ends. The diode laser source is stabilized to within ±100 kHz by locking its frequency to the transmission peak of a Faraday anomalous dispersion optical filter (FADOF). The optical filter in the receiver uses two FADOFs that are linked to eliminate the multipeak structure and achieve a single-peak bandwidth of ~1 GHz. The detection sensitivity of this system is 23 times higher than that of a system with a traditional interference filter.

Excited state Faraday anomalous dispersion spectrum of rubidium

Abstract This paper reports on the excited state Faraday anomalous dispersion spectrum (FADS) of rubidium based on transition 5 P 3 2 → 5 D 5 2 . Theoretical analysis and experimental studies have been made. The results showed that the peak transmission occurred at the central frequency of the transition, there was an optimal magnetic intensity at a certain temperature and pump power, and peak transmission increased with the enhancement of pump power. 16% transmission was predicted when the density of 5 P 3 2 atoms was sufficient.

Study of Faraday anomalous dispersion spectra of the hyperfine structure of Rb D2 lines

Natural rubidium is a mixture of the two isotopes, 85Rb and 87Rb, the natural abundances of which are 72.2 and 27.8 percent, respectively. Taking into account their hyperfine structure, we have calculated the Faraday anomalous dispersion spectra (FADS) of Rb D2 lines in different magnetic fields and observed them experimentally. The theoretical calculations are in good agreement with the experimental results. In this paper, we also discuss the results.

A STUDY OF THE PHYSICAL PROPERTIES OF ZEEMAN ABSORPTION FARADAY ANOMALOUS DISPERSION OPTICAL FILTER

This paper reports what is to our knowledge the first demonstration of Zeeman absorption Faraday anomalous dispersion optical filter (hereafter abbreviated to FADOF/Zeeman). The mutual relations among passband, tuning capability, cell temperature and magnetic field of FADOF/Zeeman have been studied theoretically and experimentally. The results showed that the single passband of FADOF/Zeeman was about 1 GHz, which is 3 times less than the passband of FADOF. The tuning capability was about 1 GHz/0.01 T.

Improvement of the Two-Beam Coupling Response Time in Photorefractive Double-Doping KNbO3

We report experimental studies on the photorefractive response of KNbO3 doubly doped with manganese and rubidium, iron and rubidium, respectively. Two-beam coupling response time in KNbO3:Mn:Rb is 3 to 10 times shorter while the two-beam coupling gain coefficient remains almost the same when compare with that in KNbO3:Mn. On the other hand, under similar conditions, two-beam coupling response time in KNbO3:Fe:Rb is 6 times faster than that in KNbO3:Fe.

High spatial resolution of an optical addressing spatial light modulator made by photorefractive semi-insulting multiple quantum wells

Effects of Ga substitution for Sn on the structure and magnetic properties of TbMn6Sn6-xGax (x=0.0-1.2) compounds have been investigated by means of x-ray diffraction, magnetization measurement and Sn-119 Mossbauer spectroscopy. The substitution of Ga for Sn results in a decrease in lattice constants and unit-cell volumes. The magnetic ordering temperature decreases monotonically with increasing Ga content from 423 K for x=0.0 to 390 K for x=1.2. At room temperature, the easy magnetization direction changes from the c-axis to the ab-plane. This variation implies that the substitution of Ga for Sn leads to a decrease in the c-axis anisotropy of the Tb sublattice. An increase in the non-magnetic Ga concentration results in a monotonic decrease of the spontaneous magnetization M-s at room temperature. Since there are three non-equivalent Sn sites, 2c (0.33, 0.67,0), 2d (0.33, 0.67,0.5) and 2e (0,0,0.34) in the TbMn6Sn6-xGax compounds, the Sn-119 Mossbauer spectra of the TbMn6Sn6 and TbMn6Sn5.4Ga0.6 compounds can be fitted by three sextets. The hyperfine fields (HFs) decrease in the order of HF(2d)>HF(2e)>HF(2c), which is in agreement with the magnetic structure.

Study of the four-wave mixing diffraction efficiency of longitudinal-field multiple-quantum-well photorefractive device grown at low temperature

We investigate the relationship between the beam intensity and the four-wave mixing diffraction efficiency of the longitudinal-field multiple-quantum-well (LMQW) photorefractive device grown at low temperature. A optimum beam intensity is found. We also explain the different mechanisms of the beam intensity effect on the diffraction efficiency of the LMQW device and the transverse-field MQW device. Some advice on how to improve the diffraction efficiency is given.