Laser Module Research Articles

Novel laser hair removal in all skin types.

Laser has been long accepted as a solution for excess or unwanted hair growth yet traditional lasers are not always ideal for safe and effective outcome for all skin types and hair characteristics. A diode laser module combining three wavelengths (755, 810, and 1064 nm) in a single pulse was developed to provide a fast and long-term solution for subjects with various profiles. To evaluate the safety and efficacy of a Triple wavelength diode laser module for hair removal treatment in all skin types (Fitzpatrick I-VI). This was a prospective, dual centered, single-arm study. Subjects were treated with a novel diode laser module. Thirty-six subjects were enrolled, sixteen with Fitzpatrick skin types I-IV (46%) and twenty with Fitzpatrick skin types V-VI (54%). Treatment areas were axilla and bikini lines. Subjects underwent 4 treatment sessions at 6 weeks ± 5 days intervals and attended a follow-up visit 3months after the last treatment session. 2D digital photographs were taken at baseline and at the follow-up visit, and a hair count was conducted by three blinded evaluators. A significant reduction in hair count between baseline and the 3-month follow-up visit was observed in both axilla and bikini lines for all skin types. The mean hair reduction was 41.5± 19.4% and 48.1± 20.9% in the axilla and bikini line, respectively. A significant hair reduction was also observed within skin type groups; mean hair reduction 45.5± 16.9% and 40.3± 17.2% in skin types I-IV and V-VI, respectively, indicating similar efficacy for both light and dark skin types. No serious adverse events were reported. This study demonstrates that the Soprano Titanium laser platform is safe and effective for hair removal treatment in all skin types.

Simultaneous Detection of Gas Concentration and Light Intensity Based on Dual-Quartz-Enhanced Photoacoustic-Photothermal Spectroscopy

This research proposes a method for the simultaneous acquisition of the second harmonic (2f) signal of quartz-enhanced photoacoustic spectroscopy (QEPAS) and the first harmonic (1f) signal of quartz-enhanced photothermal spectroscopy (QEPTS) based on the dual-quartz-enhanced photoacoustic–photothermal spectroscopy. The laser beam is first wavelength-modulated by the injection current and then intensity-modulated by an acoustic-optic modulator. The frequency of the wavelength modulation is half of the QTF1 resonant frequency, and the frequency of the intensity modulation is equal to the QTF2 resonant frequency. A modulated laser beam traveled through the two arms of the QTF1 and converged on the root of the QTF2. The 2f photoacoustic and 1f photothermal signals are concurrently obtained using the frequency division multiplexing technology and lock-in amplifiers, which allows the simultaneous detection of the gas concentration and laser light intensity. CH4 is chosen as the target gas, and the variations of the 2f photoacoustic and 1f photothermal signals are evaluated at various gas concentrations and light intensities. According to the experiments, the amplitude of the 1f photothermal signal has a good linear connection with light intensity (R2 = 0.998), which can be utilized to accurately revise the 2f photoacoustic signal while light intensity fluctuates. Over a wide range of concentrations, the normalized 2f photoacoustic signals exhibit an excellent linear response (R2 = 0.996). According to the Allan deviation analysis, the minimum detection limit for CH4 is 0.39 ppm when the integration time is 430 s. Compared with the light intensity correction using a photodetector for the QEPAS system, this approach offers a novel and effective light intensity correction method for concentration measurements employing 2f analysis. It also has the advantages of low cost and compact volume, especially for mid-infrared and terahertz systems.

A Novel Optical-Based AC Calorimetry Method to Measure In-Plane Thermal Conductivity of Small-Scale Samples

Conventional ac-calorimetry method could accurately measure the in-plane thermal diffusivity of suspended thin films but cannot be applied to small-scale samples due to the large sample size required by this method. This work proposes a novel optical-based ac-calorimetry method that circumvents the limitations of the conventional ac-calorimetry method. This new method uses a modulated continuous-wave laser to heat the sample periodically, and another continuous-wave laser to detect the sample’s temperature response on the surface at different distances from the heating spot via the principle of thermoreflectance. Since this method uses highly focused laser beams with micrometer-scale spot diameters for optical heating and temperature sensing, and this method uses the state-of-the-art thermal model of 3D anisotropic multilayers for signal processing, this method can accurately measure the in-plane thermal conductivity of suspended and supported thin films and bulk materials with sub-millimeter-scale lateral sizes, with a typical measurement uncertainty of less than 5%. This paper describes the details of this technique, including the basic principle, test device, signal acquisition, data processing, and uncertainty analysis. This technique is demonstrated through measurements of a standard sapphire sample, with the phase and amplitude approaches of ac-calorimetry compared. This technique is also compared with some other related optical-based thermal methods for their pros and cons in the end.

Industry 4.0-Based Framework for Real-Time Prediction of Output Power of Multi-Emitter Laser Modules during the Assembly Process

The challenges of defects in manufacturing and assembly processes in optoelectronic industry continue to persist. Defective products cause increased time to completion (cycle time), energy consumption, cost, and loss of precious material. A complex laser assembly process is studied with the aim of minimising the generation of defective laser modules. Subsequently, relevant data were gathered to investigate machine learning and artificial intelligence methods to predict the output beam power of the module during the assembly process. The assembly process was divided into a number of chain steps, where we implemented a bespoke framework of hybrid feature selection method alongside artificial neural networks (ANNs) to formulate the statistical inferences. A review of existing learning methods in manufacturing and assembly processes enabled us to select XGBoost and random forest regression (RFR) as the two methods to be compared with ANN, based on their capabilities; ANN outperformed both of them, as it avoided overfitting and scored similar test metrics in the majority of the assembly steps. The results of the proposed solution have been validated in a real production dataset, even showing good predictive capability in the early steps of the assembly process where the available information is limited. Furthermore, the transferability of the framework was validated by applying the proposed framework to another product that follows a similar assembly process. The results indicated that the proposed framework has the potential to serve as the foundation for further research on laser modules’ sophisticated and multi-step assembly lines.

Nanosecond compressive fluorescence lifetime microscopy imaging via the RATS method with a direct reconstruction of lifetime maps.

The RAndom Temporal Signals (RATS) method has proven to be a useful and versatile method for measuring photoluminescence (PL) dynamics and fluorescence lifetime imaging (FLIM). Here, we present two fundamental development steps in the method. First, we demonstrate that by using random digital laser modulation in RATS, it is possible to implement the measurement of PL dynamics with temporal resolution in units of nanoseconds. Secondly, we propose an alternative approach to evaluating FLIM measurements based on a single-pixel camera experiment. In contrast to the standard evaluation, which requires a lengthy iterative reconstruction of PL maps for each timepoint, here we use a limited set of predetermined PL lifetimes and calculate the amplitude maps corresponding to each lifetime. The alternative approach significantly saves post-processing time and, in addition, in a system with noise present, it shows better stability in terms of the accuracy of the FLIM spectrogram. Besides simulations that confirmed the functionality of the extension, we implemented the new advancements into a microscope optical setup for mapping PL dynamics on the micrometer scale. The presented principles were also verified experimentally by mapping a LuAG:Ce crystal surface.

Optical switch by direct modulated laser diode using fiber laser for pulse picking

Optical switch by direct modulated laser diode using fiber laser for pulse picking

On‐Chip Metaline for Multiport Beam Splitting

AbstractWave shaping plays an important role in on‐chip signal processing. However, previously reported photonics elements exhibit limited control capabilities or require complex nanofabrication techniques. Here, an on‐chip metadevice is proposed for multiport beam splitting based on a 1D slots array on the silicon‐on‐insulator platform, which has the advantages of high efficiency, full 2π phase shift, and an easy design scheme. The proposed metadevice is experimentally demonstrated at 1550 nm, which shows different numbers of beam splits. This design provides a new solution for on‐chip beam splitting, which has great potential in wide applications such as signal processing, on‐chip laser modulation, on‐chip neural network, etc.

Sub-nanometer measurement of transient structural changes in dye-doped polystyrene microspheres

We present an interferometric spectral-domain optical coherence tomography microscopy setup to detect structural changes using interference of light reflected from different interfaces of the sample. We induce a reproducible nanometer-scale size change in dye-doped 10-µm polystyrene microspheres by the release of Stokes shift energy of dye molecules inside the microspheres, excited by a modulated 532-nm laser. The resulting optical path length difference was measured with a sensitivity of 0.4 p m / H z limited by photodetection noise, and reveals elastic as well as inelastic responses, which opens up possibilities for measuring the response of cell-sized biological objects.

Extraction of thermal conductivity using phonon Boltzmann Transport Equation based simulation of frequency domain thermo-reflectance experiments

The multidimensional phonon Boltzmann Transport Equation (BTE) was solved numerically in cylindrical coordinates and in time domain to simulate a Frequency Domain Thermo-Reflectance (FDTR) experimental setup. The phase lag between the pump and probe laser signals were computed for a pump laser modulation frequency ranging from 20 to 200 MHz. Results were obtained both with and without the inclusion of optical phonons, as well as with two different relaxation time-scale expressions (Holland versus Broido) for scattering, obtained from the literature for silicon. It was found that inclusion of optical phonons significantly improved the agreement between the measured and the computed phase lag. Subsequently, the thermal conductivity was extracted by fitting the Fourier heat conduction equation results—also solved numerically in time domain—to the measured and computed (using BTE) phase lag values. While both relaxation time-scales exhibited thermal conductivity suppression, a clear superiority of one time-scale expression over the other could not be established. With the Broido time-scale, the thermal conductivity extracted from BTE calculations overpredicted the value extracted from experiments regardless of whether optical phonons were included in the calculations. In contrast, with the Holland time-scale, the extracted thermal conductivity value overpredicted the value extracted from experiments when optical phonons were included, but underpredicted the value when optical phonons were excluded.

A Novel Intelligent Rebound Hammer System Based on Internet of Things

In order to improve the test efficiency of concrete strength and ensure measured data reliability, we present a novel intelligent rebound hammer system which is based on the Internet of Things (IoT) and speech recognition technology. The system uses a STM32F103C8T6 microcontroller as the Main Control Unit (MCU), and one BC26 module as the communication unit, combined with a LD3320 voice recognition module and TOF050H laser ranging sensor to achieve the function of phonetic transcription and laser ranging. Without the need for traditional multi-person collaboration and burdensome data transfer, the system can collect the data of rebound value and location information and send them to the remote cloud information management system automatically in real time. The test results show that the system has high measuring accuracy, good data transmission stability and convenient operation, which could provide guidance for other types of non-destructive testing equipment designs.

Histopathological effects of laser fiber diameter in different laser modulations: an experimental exvivo study

We aimed to compare the histopathological effects of different laser fiber diameters on kidney tissue using different modulations of holmium laser. An ex vivo trial was performed employing veal kidneys. A 100 W HoYAG laser device (Cyber Ho, Quanta System, Samarate, Italy) was employed, accompanied by 550 μm and 272 μm laser fibers for all experimental procedures. Incision depth (ID), vaporization area (VA), coagulation area (CA), surface section (SS), lateral effect (LE) and total laser area (TLA, calculated as VA+CA) were assessed. Histopathological measurement results of different laser fiber diameters were compared in Standard mode (SM) and Virtual BasketTM (VB) mode. In SM and VB, a statistically significant difference was found in the mean CA values between 272 (μm) and 550 (μm) laser diameters (p: 0.02 and p<0.001, respectively). In SM, the lowest and highest mean CAs were observed with the 272 (μm) lasers at 0.5 J-40 Hz and 1.5 J-40 Hz laser configurations (0.263±0.003 mm2 and 1.353±0.015 mm2, respectively). In VB, the lowest and highest mean CAs were observed with the 550 (μm) at 0.5 J-20 Hz and 1 J-20 Hz laser settings (0.987±0.014 mm2 and 1.969±0.029 mm2, respectively). We found that both SM and VB modulations have higher CA values, a measure of hemostasis, in 550 μm fibers compared to 272 μm fibers.

Optimization and control of cold atom interference phase shift based on laser double-sideband suppression

Using the electro-optical modulation method to generate Raman beams for cold atom interference is one of the better methods for constructing a more compact and robust laser system. But this way will generate some residual sidebands resulting in the additional interference phase shift, which can affect the measurement accuracy of cold atom interferometer. In order to weaken the effect of laser modulation sidebands on the phase shift of cold atom interference, a double-sideband suppressed-carrier modulation laser system for cold atom interference is constructed. Based on the designed laser system, the principle of double-sideband generation and suppression is analyzed in detail, and some residual sidebands are adjusted and controlled. Moreover, some important optical parameters that affect the phase shift of cold atomic interference, such as the initial distance between the Raman retro-reflection mirror and the atomic cloud, the interrogation time between two adjacent Raman pulses, the laser modulation depth and the initial velocity of the atomic cloud, are discussed and optimized. By optimizing these relevant parameters, the influence of residual modulation sidebands on the phase shift of cold atomic interference is weakened drastically. The research results indicate, making use of the method of double-sideband suppression, the phase shift of cold atomic interference can be optimized to 0.7 mrad when the initial distance between the Raman retro-reflection mirror and the atomic cloud is 105 mm, and the interrogation time between two adjacent Raman pulses is 82 ms. More importantly, this work can provide a method for weakening the influence of Raman sideband effect on the phase shift of cold atom interferometer, and the corresponding laser system can be applied to other inertial sensors such as atomic gravimeter or atomic gravity gradiometer.

Quartz-Enhanced Photoacoustic Spectroscopy for One-Health

We report on the development of Quartz-Enhanced Photoacoustic Spectroscopy (QEPAS) technology to detect 8 different air pollutants, namely CH4, NO2, CO2, N2O, CO, NO, SO2 and NH3, with the same acoustic detection module and interchangeable laser sources, to prove the modularity of the technique as well as the adaptability to different lasers. For each gas species, the fine structure of the infrared absorption bands has been simulated by using HITRAN database. Each gas species was detected with an ultimate detection limit well below their typical natural abundance in air even with a signal integration time as low as 0.1 s.

Theoretical and experimental study of inversion of spectral absorption function using experimental data of laser absorption spectrum with slow scanning and fast modulation of wavelength

Based on the tested data of laser absorption spectra, a matrix slicing method is proposed to invert the absorption function of spectral lines by using the two parameters of laser modulation frequency and laser scanning range as well as transmitted wave signal and reference wave signal under the condition of slow uniform scanning wavelength and fast periodic modulation wavelength. When the modulation is single frequency sinusoidal modulation, an accurate contour of the spectral line absorption function can be obtained by using the matrix data consisting of the values of the transmitted wave signal by the reference wave signal through the minimum value of two slice integrals with the interval of half modulation period, and the amplitude of modulation can be estimated. When the fast modulation of the wavelength is distorted to the multi-frequency superposition modulation, the absorption function is also formed by using the complementarity of multiple slices. The method above is utilized for investigating a real absorption function inversion process involving multiple overlapping absorption lines in the range of the scanning wavelengths. Moreover, the scanning range of laser wavelength can be calibrated by the interval parameters of several spectral lines in the scanning wavelength range. The absorption function of CO at 4300.700 cm<sup>–1</sup> and CO<sub>2</sub> at 6336 cm<sup>–1</sup> are successfully obtained by using this matrix slice method for experimental verification.

Analysis of micro-relief of biofilm of yeast Candida albicans of basic plastics by the method of laser modulation interference microscopy.

The development of mycotic colonization of the base surface with further biodegradation of acrylic plastics is currently of undoubted interest. The oral cavity is a favorable ecological niche for colonization by fungi and their subsequent possible invasion into the epithelium of the oral mucosa. The method of modulation interference laser microscopy is of considerable interest to researchers in medicine in the context of obtaining the necessary information about the morphological characteristics of microbial cells and the microbiome community as a whole during the colonization of a certain ecological niche in the human body. Purpose of the study: to analyze the microrelief of the biofilm of yeast-like fungi of the species Candida albicans of base plastics of the hot type of polymerization using the method of laser modulation interference microscopy. An experimental study was carried out in order to study biofilms of yeast-like fungi of the genus Candida on samples of basic plastics, an image of a biofilm of yeast-like fungi of the species Candida albicans was obtained on the surface of a plastic of a hot type of polymerization (polymethyl methacrylate) in the visualization of the phase portrait, a description of its horizontal and vertical bioprofile. As a result of the research, the heterogeneous structure of the biofilm was determined, due to the different density and accumulation of cells along the surface, the characteristics of the surface were established in accordance with the roughness criteria. The microrelief parameters on a separately arbitrarily selected section line allow one to determine the characteristics of the biofilm in the required area and make it possible to judge the nature of its formation in a certain biological niche.

Online tomography algorithm based on laser absorption spectroscopy

Conventional calibration-free wavelength modulation spectroscopy generally requires complex absorption spectrum simulations in combination with spectral databases and laser modulation parameters, placing high demands on the accuracy of a priori spectral parameters and hardware parameters. Meanwhile, inappropriate initial values can increase the computation time and even lead to local optimal solutions. In order to improve the computational efficiency, a rapid calibration-free wavelength modulation spectroscopy to obtain the integrated absorbance is presented in this work. First, this method is computationally efficient, requiring only algebraic calculations by using the 2nd, 4th, and 6th harmonic center peak height parameters to obtain the integrated absorbance, eliminating the need for computationally intensive harmonic fitting calculations. Secondly, this method has low dependence on the spectral database, requiring only line intensity and low-state energy level spectral parameters. Finally, this method is highly adaptable and does not require scanning the complete absorption spectral line shape, which solves the problem of incomplete harmonic signals caused by the conventional method at high temperature and high pressure due to the broadening of the absorption spectral line. This method has previously been used only for line-of-sight measurements at low-frequency experimental signals in stable environments, and for calculating the integrated absorbance at average temperature, concentration and pressure states. In this work, the method is applied to non-uniform complex combustion field tomography and combined with the proposed tomographic system to achieve online reconstructing temperature and concentration distributions. The accuracy and computational efficiency of the method in obtaining the integrated absorbance are verified by numerical simulations and experiments on the butane burner flame. The results show that the presented method is consistent with the reconstructed distribution compared with the conventional wavelength modulation method, with a maximum relative deviation of only 0.94% from the measurement and 3.5% from the thermocouple measurement, verifying the accuracy of the method. The computational efficiencies of the two methods for obtaining the integrated absorbance are analyzed. The average calculation time per path is 0.15 s for the present method and 21.10 s for the conventional method. The calculation efficiency of the present method is at least two orders of magnitude higher than that of the conventional method, which provides a fast and reliable research method and technical means to realize the industrial-grade online reconstruction of temperature and concentration distribution of combustion fields.

Design of Defect-based Value Retention Strategies in Optoelectronic Products – Industrial Case Study on Multi-Emitter Laser Diodes

As applications for optoelectronic products expand, the producers of laser modules face a challenge to reduce in-line waste as an attempt to improve their economic and sustainability performance. To achieve this goal, a feasible strategy is the recovery of value through the re-use of components and materials from non-conforming parts. This value retention strategy relies on efficient disassembly and re-manufacturing operations. As a matter of fact, the disassembly of optoelectronic products remains to be investigated. Typically, the properties of optical components irreversibly change during the assembly stage, particularly during bonding and fixation stages, hence the complexity of de- and re-manufacturing processes emerges. In this paper, the disassembly and requalification of laser modules are studied, and techniques to unlock defect-reuse potential are explored. The focus of this paper is to explore industry-ready techniques and apply them within the context of value retention practices to in-line defective products. The industrial case addresses two product families with increasing complexity in component functional inter-dependencies. The paper presents a method for assigning quality classes to failed products by analyzing the product structure and historical failure data, which in turn triggers the defect management strategies for product requalification and components reuse. The paper contributes to the formalization of cost analysis in pursuing the value retention strategies for different classes, while taking into consideration the costs of disassembly, rework, and disposal.

1.3-μm 2.8-ns electro-optical cavity damping Nd:YVO<sub>4</sub> laser

<sec>1.3-μm Nd laser has significant practical applications in various fields, such as fiber communication, medical treatment, frequency conversion, and scientific research. Many applications of a 1.3-μm laser, particularly frequency conversion, benefit greatly from a short pulse width with high peak power. In the paper, an electro-optical cavity dumping Nd:YVO<sub>4</sub> laser at 1342 nm wavelength is studied theoretically and experimentally.</sec><sec>The pulse width for an electro-optical cavity dumping laser is determined by the optical length of the cavity. A narrower pulse width is obtained by reducing the length of the cavity and the round trip time of the laser in the cavity. However, when the round trip time in the cavity approaches to the falling edge time of the electro-optical switch, shortening the length of the cavity will not obtain a narrower pulse width, and the falling edge time of the electro-optical switch will influence the laser pulse width. The temporal characteristics of the laser pulse are simulated when the falling edge time of the electro-optical switch is close to the round trip time in the cavity.</sec><sec>The influence of the falling edge time of the electro-optical switch on the laser pulse duration is analyzed theoretically. The modified rate equation is used to study the relationship between the falling edge time and the laser pulse width.</sec><sec>We demonstrate an electro-optical cavity dumping Nd:YVO<sub>4</sub> laser. The atom percent of 0.3% Nd:YVO<sub>4</sub> placed in a short Plano-concave cavity is in-band pumped by an 880 nm quasi-continuous-wave diode. A fiber-coupled diode laser module (<i>NA</i> = 0.22) with a power of 30 W is used. An LiNbO<sub>3</sub> electro-optical switch is employed for the cavity-dumping. The 1342-nm cavity-dumping laser operates at a repetition rate of 1 kHz, single-pulse energy of 0.21 mJ, and pulse width of 2.8 ns. Near-diffraction-limited beam quality with an <inline-formula><tex-math id="Z-20230713064624-1">\begin{document}$ M^2 $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20230014_Z-20230713064624-1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="14-20230014_Z-20230713064624-1.png"/></alternatives></inline-formula>value of < l.2 is achieved. The setup uses MgO:PPLN crystal to generate efficient second harmonic at 671 nm, with a pulse width of 1.8 ns. To the best of our knowledge, this is the shortest pulse duration ever obtained from 1.3 μm actively <i>Q</i>-switched Nd-doped laser.</sec>

A corrugated epsilon-nearzero saturable absorber for a high-performance 1.3 μm solid-state bulk laser.

Epsilon-near-zero (ENZ) materials with vanishing permittivity exhibit unprecedented optical nonlinearity within subwavelength propagation lengths in the ENZ region, making them promising photoelectric materials that have achieved exciting results in ultrafast pulse laser modulations. In this study, we fabricated a novel saturable absorber (SA) based on a corrugated indium tin oxide (CITO) film with a symmetrical geometry using a low-cost self-assembly process. The strong saturable absorption of the CITO film triggered by the ENZ effect at normal incidence was comparable to that of the planar indium tin oxide (ITO) film at an optimal 60° incidence (TM polarization) at 1340 nm. In addition, the strong nonlinear optical properties of the CITO film were not limited by the incident angle and polarization state of the pump laser over a wide range of 0-20°. Benefiting from the excellent saturable absorption of CITO-based SA at normal incidence, a Q-switching operation with CITO-based SA at 1.34 μm was achieved in a Nd:YVO4 solid-state laser system, obtaining pulses of a duration of 85.6 ns, which was one order of magnitude narrower than that of the planar ITO-based SA. This study presents a new strategy for developing high-performance ENZ-based SAs and ultrafast lasers.

1342 nm 2.8ns electro-optical cavity damping Nd: YVO<sub>4</sub> laser

1.3 μm Nd laser has significant practical applications in various fields, such as fiber communication, medical treatment, frequency conversion, and scientific research, etc. Many applications of a 1.3 μm laser, especially like frequency conversion, benefit much from a short pulse width with high peak power. In the paper, an electro-optical cavity dumping Nd:YVO<sub>4</sub> laser at 1342 nm wavelength has been studied theoretically and experimentally. The pulse width for an electro-optical cavity dumping laser is determined by the optical length of the cavity. A narrower pulse width can be obtained by reducing the length of the cavity and the round trip time of the laser in the cavity. However, when the round trip time in the cavity approaches to the falling edge time of the electro-optical switch, shortening the length of the cavity will not get a narrower pulse width, and the falling edge time of the electro-optical switch will influence the laser pulse width. The temporal characteristics of the laser pulse are simulated when the falling edge time of the electro-optical switch is close to the round trip time in the cavity. Influences of the falling edge time of the electro-optical switch on the laser pulse duration are analyzed theoretically. The modified rate equation is used to study the relationship between the falling edge time and the laser pulse width. We demonstrate an electro-optical cavity dumping Nd:YVO<sub>4</sub> laser. The 0.3 at.% Nd:YVO<sub>4</sub> placed in a short Plano-concave cavity is in-band pumped by an 880 nm quasi-continuous-wave diode. A fiber-coupled diode laser module (NA=0.22) with a power of 30 W was used. A LiNbO<sub>3</sub> electro-optical switch was employed for the cavity-dumping. The 1342 nm cavity-dumping laser operates at a repetition rate of 1kHz, and a single-pulse energy of 0.21 mJ is obtained with a pulse width of 2.8 ns. Near-diffraction-limited beam quality with an M<sup>2</sup> value of < l.2 is achieved. The setup provides efficient second harmonic generation at 671 nm using a MgO:PPLN crystal, and the pulse width is 1.8 ns. To the best of our knowledge, this is the shortest pulse duration obtained from 1.3μm actively Q-switched Nd-doped laser.