A Narrow-Linewidth Optical Parametric Oscillator Inserted with Fabry–Perot Etalon

Nowadays, the Fabry–Perot etalon (F–P) has been widely utilized in the optical parametric oscillator (OPO) to improve the filtering performance. In this paper, we reported an F–P etalon composed of two ultra-thin silicon wafers spaced with the air. The linewidth of the signal laser and the threshold are 0.03 nm and 0.6 W, respectively when the proposed etalon is employed to a OPO system based on the MgO-doped LiNbO3 (MgO: PPLN). A stabilized output at 1492.4 nm is obtained, and a tunable, high-precision filtering performance can be achieved by varying the gap distance of the F–P etalon arbitrarily due to its ultra-thin thickness. In addition, the F–P etalon can work on a very wide bandwidth due to its weak absorption during the infrared and terahertz waveband. The high-precision tuning capability and wide-band function of proposed etalon may benefit many applications, including spectroscopy, filtering, and optical communication.

Variable Optical Buffer Using EIT in Three Level System Based on Semiconductor Conical Quantum Dots

A variable semiconductor optical buffer based on the electromagnetically induced transparency (EIT) in a three level conical quantum dot system (CQD) is theoretically investigated. The system is interacting with two (control and signal) laser beams. Signal light with subluminal velocity is possible in such system through the quantum interference effect induced by the control pump field. We investigate the refractive index and absorption spectra of the QD waveguide at different pump levels, which exhibit an optimal pump power for maximum slow-down factor (SDF). The group velocity SDF is theoretically analyzed as a function of the pump intensity at different broadened linewidths. The present study is based on the assumption that the medium is homogeneous. In this paper, a SDF as a function of CQD radius was studied. The simulation results indicate that the SDF increases with decreasing CQD radius.

All-Optical Switching Based on the Plasma Channel Induced by Laser Pulses

We display a theoretical and experimental study of all-optical switching for signal lasers based on the plasma channel induced by the control laser. Using the plasma channel generated in the carbon disulfide (CS2) solution, the signal light can be modulated as some spatial distributions including unchanging, ring-shaped beam, and other intensity profiles. The modulation on the signal light can be conveniently adjusted by changing the control light’s incident intensity distribution. We can infer the dark spot shape in the modulated signal laser through the intensity profile of control laser beam. These results provide the great potential of plasma channel induced by lasers as an all-optical switching for various optoelectronic applications.

Wireless Energy Supply to Aircraft Structural Health Monitoring Nodes Using Ultrasonic Lamb Waves

This article is based on research done during the author’s PhD at Cardiff University, UK. A prototype of a novel wireless energy transmission system aimed at the use with wireless aircraft structural health monitoring (SHM) sensor nodes is described. The system uses ultrasonic guided plate waves (Lamb waves) to transmit energy along an aluminium plate, similar to those used in aircraft structures. Three types of piezoelectric transducers generating and receiving the ultrasonic vibration were compared. The Smart Material MFC M8528-P1 was found to achieve the best performance, allowing the transmission of 17 mW across a 54 cm distance, while being driven with a 20 V signal. Laser vibrometer imaging and LISA software simulation of the Lamb wave propagation in the experimental plate were also performed. Based on these, ideas for a further development of the system were proposed.