Advancements and applications of position-sensitive detector(PSD): a review

This paper presents a review of the position-sensitive detector(PSD) sensor, covering different types of PSD and recent works related to this field. Furthermore, it explains the theoretical concepts and provides information about its structure and principles of operation. Moreover, it includes the main information about the available commercial PSDs from different companies, along with a comparison between the common modules. The PSD features include high position resolution, fast response, and a wide dynamic range. These features make it suitable for various fields and applications, such as imaging, spectrometry, spectroscopy and others.

Editorial Special issue on recent advances in hybrid control theory and applications

The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory. In recent years control problems have been arising with increasing frequency in widely different areas, which cannot be addressed using conventional control techniques. The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where presence of large uncertainties as well as nonlinearities plays a major role. For instance, the design of unmanned aircraft, unmanned underwater vehicles, and automatic driving systems for automobiles are all typical examples of such difficult control problems. The large uncertainties concerning the plant may arise due to large external disturbances, large parameter variations because of faults in the system, or failure of some of the subsystems. In such cases, the controller has to determine the specific situation that exists at any instant, and take the appropriate control action. Accomplishing this rapidly, accurately, and in a stable fashion is the objective of control design.

All-fiberized and narrow-linewidth 5 kW power-level fiber amplifier based on a bidirectional pumping configuration

In this paper,an all-fiberized and narrow-linewidth 5 kW power-level fiber amplifier is presented.The laser is achieved based on the master oscillator power amplification configuration,in which the phase-modulated single-frequency laser is applied as the seed laser and a bidirectional pumping configuration is applied in the power amplifier.The stimulated Brillouin scattering,stimulated Raman scattering,and transverse mode instability effects are all effectively suppressed in the experiment.Consequently,the output power is scaled up to 4.92 kW with a slope efficiency of as high as approximately 80%.The 3-dB spectral width is about 0.59 nm,and the beam quality is measured to be M^(2)~1.22 at maximum output power.Furthermore,we have also conducted a detailed spectral analysis on the spectral width of the signal laser,which reveals that the spectral wing broadening phenomenon could lead to the obvious decrease of the spectral purity at certain output power.Overall,this work could provide a reference for obtaining and optimizing high-power narrow-linewidth fiber lasers.

Scaling diode-pumped, high energy picosecond lasers to kilowatt average powers

Recent results in the development of diode-driven high energy, high repetition rate, picosecond lasers, including the demonstration of a cryogenic Yb:YAG active mirror amplifier that produces 1.5 J pulses at 500 Hz repetition rate(0.75 kW average power) are reviewed. These pulses are compressed resulting in the generation of ~5 ps duration,1 J pulses with 0.5 kW average power. A full characterization of this high power cryogenic amplifier, including atwavelength interferometry of the active region under >1 kW average power pump conditions, is presented. An initial demonstration of operation at 1 kW average power(1 J, 1 k Hz) is reported.