q switched laser

We present an intra-cavity frequency doubled Q-switched diode-pumped alexandrite ring-laser directly emitting in the UV at 386 nm. Using LBO as nonlinear crystal, the laser yields a pulse energy up to 3 mJ at 500 Hz with an excellent beam quality of M2  = 1.1. The pulse length is about 920 ns, allowing for very narrow bandwidth in single longitudinal mode operation. The optical-to-optical efficiency for the UV laser is > 9% and almost unchanged compared to the fundamental laser...

In this paper, two-dimensional Graphdiyne and Hexakis-[(trimethylsilyl)ethynyl]benzene nanosheets were prepared using the liquid-phase exfoliation method and were then successfully applied to 1.06 µm passively Q-Switched all-solid-state lasers. The Hexakis-[(trimethylsilyl)ethynyl]benzene was applied for the first time in passively Q-Switched all-solid-state lasers, as we know. For Graphdiyne, the Q-Switched pulse achieved a narrowest pulse width of 415 ns, a maximum repetition frequency of 244...

We present an all-fiber passively mode-locked (ML) laser with a nonlinear multimode interference (NLMI)-based saturable absorber (SA) capable of generating five pulse modes. The SA consists of two centrally aligned graded index multimode fiber (GIMF) with different diameters (105-50 µm) and features a widely adjustable transmission with saturable/reverse-saturable absorption. Based on this, dissipative soliton (DS), Q-switched rectangular pulse (QRP), dissipative soliton resonance (DSR), noise-like pulse (NLP) and bright-dark pulse pairs (BDP) are observed at three dispersions without additional filter...

We present a simple, compact source of sub-nanosecond pulsed red radiation, based on cascaded nonlinear optical processes-degenerate optical parametric generation and sum-frequency generation-performed with a sample of aperiodically poled lithium niobate pumped by passively Q-switched 1.064 µm Nd:YAG laser. This system does not require feedback from an optical cavity; a single pass of the short pump is all that is required to obtain the cascaded processes, which shortens the output pulse. When pumped with a 1...

The ongoing advancement of Ti:sapphire femtosecond laser technology has drawn increasing attention to high repetition rate, high-energy green lasers as ideal pump sources for Ti:sapphire regenerative amplifiers. This study employed a neodymium-doped yttrium lithium fluoride (Nd:YLF) as the gain medium, supplemented with side-pumped laser diodes, acousto-optic Q -switching, and intracavity frequency doubling technologies. The results demonstrated a repetition rate ranging from 1-10 kHz, a pulse width of less than 100 ns, and a single pulse energy exceeding 50 mJ at 527 nm green light output...

This paper demonstrates a high-energy, single-longitudinal-mode (SLM), actively Q -switched fiber laser based on the injection seeding technique. The large-mode-area double-cladding fiber is used as the gain medium to improve energy storage. Simultaneously, by using the linear electro-optic effect of the negative uniaxial crystal ( β - B a B 2 O 4 , BBO), a matching frequency-shift-free Q -switch with high damage threshold and high extinction-ratio is designed. Before reaching the stimulated Brillouin scattering threshold, the SLM Q -switched pulses can be achieved with energy higher than 15 µJ over a wide range of repetition rates from 10 to 80 kHz, and the maximum output power reaches 1...

BACKGROUND: Melasma is a common pigmentary and photoaging disorder. Although various treatments, including 1,064-nm Q-switched neodymium-doped yttrium aluminum garnet (QS-Nd: YAG) laser toning, are available for melasma, results are often unsatisfactory. OBJECTIVE: We aimed to determine the efficacy and safety of 532-nm QS-Nd: YAG laser (shortwave toning) in patients with melasma and facial rejuvenation. METHODS: Fifty-two patients were recruited to receive either 1,064-nm QS-Nd: YAG laser or 532-nm QS-Nd: YAG laser every 2 weeks for 8 sessions and a 2-month follow-up visit in a randomized controlled double-blinded study...

This paper presents the investigations toward the direct use of bentonite clay (Al2 H2 O6 Si) nanoparticles to act like a saturable absorber (SA) for the Q-switched pulse operation of an erbium-doped fiber laser (EDFL). The measured results reveal that with the incorporation of bentonite clay nanopowder as a SA, an EDFL is realized with a Q-switching mechanism starting at a pump power of 30.8 mW, and a Q-switched emission wavelength was noticed at 1562.94 nm at 142 mW pump power. With an increased pump from 30...

TiB2 nanoparticles with a bandgap of 0 eV were prepared, and the corresponding nonlinear optical response at 2.85 μm was investigated. Employing a TiB2 as a saturable absorber, a 2.85 μm pulsed Er:Lu2 O3 crystal laser with an average output power of 1.2 W was achieved under a maximum pump power of 9.51 W. Laser pulses with durations of ~203 ns were delivered at a repetition rate of 154 kHz, which corresponds to a pulse energy of ~7.8 µJ and a peak power of 39.3 W. As far as we know, the result represents the highest average output power from all Q-switched Er:Lu2 O3 crystal lasers...

Nevus of Ota or congenital oculodermal melanosis (ODM) is characterized by brown or blue/gray asymptomatic brown or blue/gray flat lesions of the skin, mucosae, episcleral/sclera, and uvea, which are located near the trigeminal nerve's ophthalmic and mandibular branches. The main ophthalmic complications are glaucoma and predisposition to uveal melanoma. "trichilemmal cyst" is also known as "wen" "pilar cyst" or " isthmus catagen cyst". It occurs in the scalp and mimics sebaceous cysts clinically. The swelling appears smooth in outline and is filled with cytokeratin...

We report, for the first time to our knowledge, a demonstration of robust waveguide lasing near 2.7-2.8 µm in an erbium-doped fluoride host. Femtosecond laser inscription was employed to fabricate 50- and 70-µm diameter channeled waveguides inside an Er3+ :YLiF4 crystal. The best power performance was obtained with the 70-µm diameter waveguide and 16% transmitting output coupler. The propagation loss and refractive index contrast were measured as 0.23 dB/cm and 7.1 × 10-4 , respectively, for the 70-µm diameter waveguide...

A highly powerful nanosecond pulsed deep-red laser was demonstrated by intracavity second-harmonic generation of an actively Q-switched Nd:YLF dual-crystal-based KGW Raman laser in a critically phase-matched lithium triborate (LBO) crystal. The first-Stokes fields at 1461 and 1490 nm driven by the 1314 nm fundamental laser were firstly produced by accessing the Raman shifts of 768 and 901 cm-1 in the KGW crystal, respectively, and thereafter converted to the deep-red emission lines at 731 and 745 nm by finely tuning the phase-matching angle of the LBO crystal and carefully realigning the resonator...

A diode-pumped wavelength switchable passively Q-switched 2.3 μm Tm:YVO4 laser was demonstrated in this work. A Cr:ZnS saturable absorber was introduced into the cavity for initiating passive Q-switching. With the increase of the absorbed pump power, the passively Q-switched laser could be switched from the single wavelength of 2366 nm to the dual wavelength of 2290 and 2360 nm. The pulse duration and pulse repetition frequency could be tuned in the ranges of 0.745-1.782 μs and 2...

BACKGROUND AND AIM: There is a dearth of scholarly investigation pertaining to the effectiveness and safety of laser therapy for nevus of Ota manifestation in infants. The objective of this study is to examine the efficacy and safety of administering laser therapy at an early stage to treat nevus of Ota in infants. METHODS: A total of 102 infants below the age of one who had nevus of Ota were treated at the Laser Center at Hangzhou Third People's Hospital. The treatment approach involved a combination of the Q-switched laser (with a wavelength of 755 nm) and the Q-switched laser (with a wavelength of 1064 nm)...

BACKGROUND: With nearly 50% of the population in the United States, Italy, and Sweden tattooed with at least one tattoo, the demand for its removal has risen by 32% since 2011. Traditional removal methods, such as Q-switched (QS) laser-based tattoo removal, can be lengthy, requiring up to 20 sessions. AIM: This study presents a retrospective clinical evaluation of seven short-pulsed QS, dual-wavelength Nd:YAG laser, as an efficient alternative, that can potentially reduce the number of sessions needed as calculated by a founded scale...

In this paper, the zirconia (ZrO2 ) nanoparticles-based saturable-absorber (SA) have been incorporated in an erbium-doped fiber laser (EDFL) cavity for achieving a Q-switched pulse operation. The implementation of the zirconia nanoparticles-based powder on the fiber facet was accomplished using the index-matching gel's adhesion effect. The incorporation of SA in the laser cavity yielded a stable and self-starting Q-switched operation under 19.36 mW pump power that corresponded to the emission wavelength of 1557...

Raman spectroscopy and laser-induced breakdown spectroscopy (LIBS) are powerful tools for molecular and elemental analysis, respectively. Their combined application, however, is challenging due to the differences in the signal generation and detection characteristics. This note proposes three experimental schemes for the simultaneous application of Raman and LIBS for gas-phase diagnostics. Ring-cavity optical pulse stretchers facilitate shaping suitable pulse pairs from a Q-switched laser that enables the quasi-simultaneous detection of the Raman and LIBS signals on a single detector...

This paper provides a method to effectively suppress the severe ASE self-saturation when achieving high repetition frequency tunability with high output power and narrow pulse width in active Q-switched all-fiber lasers. By studying the regularity of the system's multi-stable state, we first ensured that the laser system operated in a steady state. Then output avoids uneven distribution of pulse energy or missing pulses due to period bifurcation state or chaos state. By adding multiple gain sub-rings within the cavity, the sub-ring structure itself indirectly mitigates the ASE self-saturation while smoothing the pulse...

We demonstrate the first ten-watt-level eye-safe intracavity crystalline Raman laser, to the best of our knowledge. The efficient high-power eye-safe Raman laser is intracavity-pumped by an acousto-optically Q-switched 1314 nm two-crystal Nd:YLF laser. Benefiting from the unique bi-axial properties of KGW crystal, two sets of eye-safe dual-wavelength Raman lasers operating at 1461, 1645 nm and 1490, 1721nm are achieved by rotating the Raman crystal. Under the launched pump power of 84.9 W and the repetition rate of 4 kHz, the maximum first-Stokes output powers of 7...

We have successfully achieved the synthesis of heterojunction consisting of WSe2 and BN, by using a liquid phase exfoliation method, and characterization of the prepared materials under the microstructure. The WSe2 /BN heterojunction was used as a saturable absorber in the Tm:YAP laser for passively Q-switched operation, and a pulsed laser with an output wavelength around 2 µm range was successfully obtained. After comparing the effects of resonators composed of different cavity mirrors, it is concluded that when the curvature radius of the input mirror is 250 mm and the transmittance of the output coupler is 2...