Optically pumped semiconductor lasers in conjunction with intra-cavity frequency conversion and tuning elements offer high continuous-wave power, narrow linewidth, and broad tunability. As a result, they are well suited to precision spectroscopic applications. We describe the development and testing of optically pumped semiconductor lasers operating at fundamental wavelengths of 1119 and 1178 nm. The fourth and second harmonic wavelengths are resonant with transitions in Mg II and Na I, respectively. We demonstrate continuously tunable, single-frequency lasers with watt-level average power at 1119, 1178, and 589 nm.
We report the results from a new class of gold vapor laser that produces 10 W of polarized high beam quality radiation at 627.8 nm with a pulse repetition frequency of 50 kHz. A highly robust laser tube is built from standard non-toxic refractory materials such as a boron nitride plasma tube. For the first time, the kinetic enhancement by the addition of hydrogen and hydrogen chloride to the laser buffer gas is demonstrated for a gold vapor laser. The frequency doubling and tripling of the fundamental beam yield 1.7 W of output at 313.9 nm and 35.5 mW of output at 209.2 nm, respectively. The frequency doubled output of the laser is used to demonstrate polymer micromachining, optical fiber-Bragg grating writing, and through-jacket long-period grating writing in photosensitive optical fiber.
The design of split disk laser is proposed and demonstrated with SiC wafer and uncoated
The optical properties of polycrystalline and single crystal Nd:YAG materials are reported. Materials include undoped, 1%, 1.5%, 2%, 4%, 6%, and 10% at. Nd doped polycrystalline YAG and undoped and 1% at. Nd doped single crystal YAG. The motivation of this paper is to determine the ideal material type and doping percentage gain media for use in a high energy 0.946
Multimode interferometer bistable laser diodes (MMI-BLDs) appeared recently as a potential candidate for implementing all-optical flip-flops. It was reported that in such MMI-BLDs, cross-gain saturation effect and saturable absorber together can control the hysteresis window characteristics; however, there was no clear description on how to analyze and estimate the effect of cross-gain saturation on hysteresis characteristics. In this paper, we present a model that can explain the experimental results reported for MMI-BLDs and predict the hysteresis behavior for such devices. The proposed simulation model can work for both symmetric and asymmetric configurations of MMI-BLDs as it considers the spatial gain overlap between the co-propagating modes inside the MMI-BLDs. This spatial overlap accounts for the discrepancies in hysteresis characteristics, i.e., hysteresis width and threshold currents, between both configurations. With the proposed model, as the asymmetric configuration provides variable spatial cross-gain overlap between the fundamental and first-order modes depending on device dimensions, hysteresis window characteristics vary accordingly.
A multiwavelength Brillouin Erbium fiber laser (MWBEFL) with double brillouin frequency spacing and Q-switching characteristics is demonstrated based on figure-of-eight configuration. The proposed MWBEFL uses a four-port circulator as a double-frequency shifter to isolate and circulate the odd-stokes signals through the Brillouin gain medium. Multiwavelength combs with 14 and 8 lasing lines and spacing of 0.16 nm are obtained by the use of 10-km long nonzero dispersion shifted fiber (NZDSF) and 2-km long dispersion compensating fiber (DCF), respectively. The Q-switched pulse trains are obtained in the proposed MWBEFL at 1480-nm pump power within 29 to 40 mW. It has repetition rates of 20.4 and 104.2 kHz with the corresponding pulse widths of 3.84 and 1.03
This paper reports on photodetection properties of the graphene-Si schottky junction by measuring current–voltage characteristics under 1.55-
A compact and low noise dual-wavelength fiber laser is demonstrated using a 70-cm-long Erbium-doped fiber loop attached to a microfiber coupler. The coupler functions to inject a 980-nm pump light as well as to tap out the output. At the maximum pump power of 8.4 mW, dual-wavelength laser is obtained at 1537.7 and 1551.4 nm with peak powers of 20.5 and 20.9 dBm, respectively. Both laser outputs are stable with a signal to noise ratio of more than 35 dB at room temperature. Both 1537.7 and 1551.4 nm lasers start to lase at threshold pump power as small as 2.5 mW with efficiencies of 0.14% and 0.10%, respectively.
We investigate theoretically the impact of optical feedback on quantum dot two-color laser dynamics when emitting from both the excited and the ground states. Detailed analysis of the laser dynamics is provided by numerical integrations and continuation techniques, as well as by analytical methods. As the feedback strength is increased the quantum dot laser undergoes a sequence of bifurcations involving steady-states, external cavity modes, self-pulsations and chaos. Furthermore, we report on two interesting mode competition results. First, the optical feedback favors the ground state emission; hence an increase of the feedback strength will generally lead to an increase of the ground state emission output power. Second, the optical feedback can select one lasing state or induce bistable switchings between different steady-states depending on the feedback strength and the injection current.
We present a method to calculate the harmonic spectrum of the radiation emitted at the interactions between intense laser beams and atoms. Our relations describe accurately, in good agreement with the experiment, important features of the harmonic spectrum and the evolution of its shape with the increase of the laser beam intensity. More specifically, for low intensities, of the order of