Search

We designed a new type of plasmonic laser source based on the Bragg reflection waveguide. This laser source is simple in structure and convenient for integration. It works under room temperature electrical pumping condition and outputs plasmonic laser with more than milliwatt power, which is much larger than those demonstrated plasmonic laser sources with power of nano-watt scale. The proposed laser works at 808 nm. The tilted light beam offered by Bragg reflection waveguide directly couples into surface plasmon polaritons in our quasi-Otto configuration.

An optical system to perform the semiconductor laser myringotomy with the help of a video display and a pilot laser was designed and manufactured.First,the 650 nm laser output from a single emitter and the 810 nm laser emitted from a laser diode array were coupled into a fiber with a core diameter of 200 μm and a numerical aperture of 0.22 by using beam shaping and wavelength beam combination technologies.Then,an achromatic lens was used to collimate the dual wavelength laser output from the optical fiber and the other achromatic lens which could move along principal axis and consequently change the spot size was used to focus the dual wavelength laser to the eardrum.Meanwhile,laser and imaging lights were coupled as coaxial by using a hot mirror and the imaging components from markets.Moreover,the location of myringotomy could be piloted by red light on a computer monitor.According to the results of measurement,the laser power output from the system can be continuously adjusted from 0 to 13.3 W,and the spot size can also be adjusted between 1-3 mm.The system can decrease the operation time and the possibility of surgery side effect;moreover,the myringotomy for children needs not any anasthesia.In addition,the system has the virtues of low volume,light weighted and high wall-plug efficiencies compared with other candidates.

A hundred-watt level semiconductor laser air cooling system was analyzed by ANSYS finite element analysis software.The temperature distribution and air cooling system of this high-power semiconductor laser module were simulated and optimized.It provides the basis of the choice program for 100 W-class high-power semiconductor laser module air cooling technology,and the relative experiment has been verified.

As 808 nm single emitter diode lasers have low output powers,they are limited to pump neodymium-doped double-cladding fiber lasers in end pumping.In order to enhance the pumping efficiency of the fiber laser by using single emitters,a fiber coupled module with several single emitter diode lasers was developed.First,the fast axis and slow axis of each diode laser were collimated by a micro-lens.Then,the output beams of diode lasers were combined with reflecting prisms.Finally,a suit of optical system designed by ourselves was utilized to expand and focus the beam into a optical fiber.Experiments show that this approach can greatly increase the brightness of the module with fiber coupled LDs.Four LDs with continuou output power of 5 W are coupled in a 105 μm multimode optical fiber with a core diameter of 105 μm and a numerical aperture of 0.2 when the working current is 5.8 A,it can offer the fiber output power of 15.22 W,coupling efficiency of 74% and the brightness over 1.4 MW/cm2·sr.

A cryogenic adsorption technique was presented to replace the machinery pump and exhaust processing system,which could provide a possible way to greatly suppress the size of a discharge-driven CW HF/DF chemical laser.As the nitrogen diluent must be used instead of helium for the cryogenic adsorption pump,the efficiency of HF/DF chemical laser would be lowered down greatly.To solve the problem,a periodically arranged supersonic nozzle array composed of slit and conical holes with a 4 mm period was developed to replace the traditional single slit transverse sonic fuel injecting gain generator.Experimental results with HF laser demonstrates that the laser output and electrical-optical efficiency by designed supersonic nozzle array have been increased from 25 W to 90 W,and 0.8% to 5.9%,respectively.Furthermore,the fuel specific efficiency has a nearly fourfold increase,which is slightly higher than that from the helium diluen.Obtained results prove that the efficiency of the nitrogen diluted discharge-driven CW HF/DF chemical laser can be greatly improved by using the devel-oped supersoinc nozzle array.

With the increase of LD application in the field of laser processing,the efficiency of the fiber coupled modular based on diode laser arrays is rather low,which can not meet the need of low costing for laser processing,so it is very important to develop a higher efficiency modular of fiber coupled diode lasers.In this paper,we achieved a higher efficiency fiber coupled module based on 8 single emitter diode lasers providing more than 32.4 W output power from a 200 microns fiber core with an numerical aperture(NA) of 0.22 at 808 nm.Power of each LD can reach to 5 Watts at operation current.More than 83% coupling efficiency of the modular has been realized.This high power LD module can be used in laser plastics processing and laser meclical treatment fields.

A disturbance compensation scheme based on a piezo-electric steering control system was presented,for the vibration of a satellite platform seriously impacted the tracking and pointing accuracy in space optical communication.A mathematical model for the piezo-electric steering system was built.Then,an adaptive controller based on an improved Least Mean Square(LMS) filter was designed,and effect factors on optimal step length choices were analyzed.For the problem of signal phase delay,an adaptive delay filter was designed not only to compensate the phase delay,but also adaptively to adjust the input signal phase to increase its convergence rate without adding the step length.Finally,a verifying experiment was performed.The results show that the remained errors after compensation are μrad magnitude and the compensation factor is over 85%.These results prove that this control scheme is valid and feasible.

A kind of beam shaping technique was presented to improve the beam quality of a semiconductor laser and to achieve the beam splitting,translating,and rearranging by a parallel plate glass stack.The experiment uses a 20-layer 808 nm semiconductor laser array designed by ourselves with the output power of 60 W per bar,19 light-emitting points of 1 μm×135 μm each and 30% filling factor to expand beam at a slow axis through a telescope system,and also uses a focusing lens to focus on both the slow axis and the fast one at the same time.Experiments show that the technique can achieve the 1 kW output power on the focal plane,focused spot of 1 mm×1 mm and coupling efficiency of 90%,which basically satisfies the needs of laser cladding and welding.