Detailed polarization properties have been examined in laser-diode-pumped (LD-pumped) micro-grained ceramic Nd:YAG lasers in different microchip cavity configurations. Stable linearly-polarized single-frequency oscillations, whose polarization direction coincide with that of an LD pump light, were observed in an external cavity scheme. While, in the case of a thin-slice laser scheme with coated reflective ends, elliptically-polarized single-frequency operations took place in the low pump-power regime and dynamic instabilities appeared, featuring self-induced antiphase modulations among counter-rotating circularly-polarized components having slightly different lasing frequencies, with increasing the pump power.
We report direct and absolute temperature measurements in a diode-end-pumped Yb:YAG crystal, using a calibrated infrared camera, with a 60-$μ$m spatial resolution. The heat transfer coefficient has been measured, for the first time to our knowledge, with four different types of thermal contact (H = 0.25, 0.28, 0.9 and 2.0 for bare contact, graphite layer, indium foil and heat sink grease respectively). The dynamics of thermal effects is also presented.
We describe an efficient laser emission from a directly grown Er3+:YAG single-crystal fiber that is resonantly pumped using a continuous-wave (CW) laser diode at 1532 nm. In a longitudinal pumping, it emits 12.5 W at 1645 nm with a slope efficiency of 32%, which is the highest ever reported for a directly grown Er:YAG single-crystal fiber laser. Using an off-axis pumping scheme, CW output powers up to 7.3 W can be reached and in Q-switched operation, the laser produces 2 mJ pulses with a duration of 38 ns at the repetition rate of 1 kHz with an M^{2} factor below 1.8. To our knowledge this is …
the realization of high repetition rate passively Q-switched monolithic microlaser is a challenge since a decade. To achieve this goal, we report here on the first passively Q-switched diode-pumped microchip laser based on the association of a Nd:GdVO4 crystal and a Cr4+:YAG saturable absorber. The monolithic design consists of 1 mm long 1% doped Nd:GdVO4 optically contacted on a 0.4 mm long Cr4+:YAG leading to a plano-plano cavity. A repetition rate as high as 85 kHz is achieved. The average output power is approximately 400 mW for 2.2 W of absorbed pump power and the pulse length is 1.1 ns.
6-mJ, 4-ns Pulse Generation at 2.09 $μ$m from a Diode-Pumped Ho:YAG Thin-Disk Laser
HiLASE Centre, Institute of Physics of the Czech Academy of Sciences（捷克科学院物理研究所 HiLASE 中心）；Celestia Energy s r.o.（Celestia Energy 有限公司）；CRYTUR, spol. s r.o.（CRYTUR 有限公司）
We present in this work a quasi-continuous-wave (CW) pentacene maser operating at 1.45 GHz in the Earth's magnetic field at room temperature with a duration of $\sim$4 ms and an output power of up to -25 dBm. The maser is optically pumped by a cerium-doped YAG (Ce:YAG) luminescent concentrator (LC) whose wedge-shaped output is embedded inside a 0.1% pentacene-doped para-terphenyl (Pc:Ptp) crystal. The pumped crystal is located inside a ring of strontium titanate (STO) that supports a TE$_{01δ}$ mode of high magnetic Purcell factor. Combined with simulations, our results indicate that CW operat…
We report on high power operation of Er:Y2O3 ceramic laser at ~1.6 μm using low scattering loss, 0.25 at.% Er3+ doped ceramic sample fabricated in-house via co-precipitation process. The laser is in-band pumped by an Er, Yb fiber laser at 1535.6 nm and generates 10.2 W of continuous-wave (CW) output power at 1640.4 nm with a slope efficiency of 25% with respect to the absorbed pump power. To the best of our knowledge, this is the first demonstration of ~1.6 μm Er:Y2O3 laser at room temperature. The prospects for further scaling in output power and lasing efficiency via low Er3+ doping and redu…
High-quality micro-lasers are key ingredients in non-linear optics, communication, sensing and low-threshold solar-pumped lasers. However, such micro-lasers exhibit negligible absorption of free-space broadband pump light. Recently, this limitation was lifted by cascade energy transfer, in which the absorption and quality factor are modulated with wavelength, enabling non-resonant pumping of high-quality micro-lasers and solar-pumped laser to operate at record low solar concentration. Here, we present a generic theoretical framework for modeling the absorption, emission and energy transfer of …
A compact frequency-doubled diode-pumped Nd:YAG master-oscillator power-amplifier laser system with programmable microsecond pulse length has been developed. Analog pulse shaping of the output from a single-frequency continuous-wave Nd:YAG oscillator, and subsequent amplification, allowed the generation of rectangular pulses with pulse lengths on the order of the Nd:YAG fluorescence lifetime. Temporally flat-top pulses of 1064 nm light with 520 mJ pulse energy, 2.6 kW peak power, and 200 $μ$s duration, with linewidth below 10 kHz, were obtained at a repetition rate of 2 Hz. Second harmonic gen…
We report experimental and theoretical study of a rotating diode-pumped Nd-YAG ring laser with active beat note stabilization. Our experimental setup is described in the usual Maxwell-Bloch formalism. We analytically derive a stability condition and some frequency response characteristics for the solid-state ring laser gyroscope, illustrating the important role of mode coupling effects on the dynamics of such a device. Experimental data are presented and compared with the theory on the basis of realistic laser parameters, showing a very good agreement. Our results illustrate the duality betwee…
We report about a novel scheme for particle detection based on the infrared quantum counter concept. Its operation consists of a two-step excitation process of a four level system, that can be realized in rare earth-doped crystals when a cw pump laser is tuned to the transition from the second to the fourth level. The incident particle raises the atoms of the active material into a low lying, metastable energy state, triggering the absorption of the pump laser to a higher level. Following a rapid non-radiative decay to a fluorescent level, an optical signal is observed with a conventional dete…
A simple and high-efficiency method for direct generation of all-solid-state single- and dual-vortex lasers operating at eye-safe wavelengths is reported in a compact diode-end-pumped Nd:YAG laser cavity. By off-axis pumping of the Nd:YAG in two orthogonal directions, the original cavity mode, fundamental Gaussian mode (TEM00), is directly transformed into first-order Laguerre-Gaussian (LG01) mode with single- or dual-vortex structures depending on the degree of the off-axis pumping. Moreover, the single- and dual-vortex lasers can be produced in simultaneous eye-safe dual-wavelength operation…
We report laser emission from single, stationary, Rhodamine B-doped glycerol/water microdroplets located on a superhydrophobic surface. In the experiments, a pulsed, frequency-doubled Nd:YAG laser operating at 532 nm was used as the excitation source. The microdroplets ranged in diameter from a few to 20 um. Lasing was achieved in the red-shifted portion of the dye emission spectrum with threshold fluences as low as 750 J/cm2. Photobleaching was observed when the microdroplets were pumped above threshold. In certain cases, multimode lasing was also observed and attributed to the simultaneous l…
We propose to generate optical vortices using a degenerate optical resonator with an intra-cavity spiral phase plate (SPP). The rays retracing skewed V-shaped paths in the resonator are phase-locked to form vortex laser with wavefront dislocation mirroring the topological charge of the SPP. Experimental demonstrations on diode-pumped solid state system using Nd:YAG crystal emitted randomly polarized optical vortices at a wavelength of 1064nm when the pump power went above 1.52W and the slope efficiency was 0.19. For long-term operations a power fluctuation of 2.2\% and pointing stability of 2.…
Lasers capable of generating attosecond X-ray pulses in the water window (282 to 533 eV) through high-order harmonic generation are normally based on inefficient, multi-stage optical parametric amplifiers or optical parametric chirped pulse amplifiers pumped by femtosecond or picosecond lasers. Here we report a very efficient single amplification stage laser based on traditional chirped pulse amplification capable of producing 3 mJ, near-transform limited 44 fs (<6 cycles), 1 kHz pulses centered at 2.5 micrometer. The 68 GW peak power is the highest value ever reached at this wavelength. In or…
Random lasers are promising in the spectral regime, wherein conventional lasers are unavailable, with advantages of low fabrication costs and applicability of diverse gain materials. However, their practical application is hindered by high threshold powers, low power efficiency, and difficulties in light collection. Here, we demonstrate a power-efficient easy-to-fabricate non-resonant laser using a deep hole on a porous gain material. The laser action in this counterintuitive cavity was enabled by nonresonant feedback from strong diffuse reflections on the inner surface. Additionally, signific…
We present a laterally emitting, coupled cavity micro fluidic dye ring laser, suitable for integration into lab-on-a-chip micro systems. The micro-fluidic laser has been successfully designed, fabricated, characterized and modelled. The resonator is formed by a micro-fluidic channel bounded by two isosceles triangle mirrors. The micro-fluidic laser structure is defined using photo lithography in 10 microns thick SU-8 polymer on a glass substrate. The micro fluidic channel is sealed by a glass lid, using PMMA adhesive bonding. The laser is characterized using the laser dye Rhodamine 6G dissolve…
