Revealing the cluster-structure-dependent red-to-green ratio transformation in Er:CaF crystals.

The evolution of Er clusters in CaF crystals has not been fully understood, making the underlying mechanism for regulating the upconversion luminescence color of Er:CaF crystals remains unclear. In this work, the first-principles calculation is combined with the synchrotron X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), as well as the dielectric spectra and absorption spectra to study the Er-doped CaF crystals. The spectral analysis reveals the potential mechanism underlying the red-to-green (R/G) ratio transformation; specifically, the cross-relaxation rates of different clusters differed significantly.

Sub-60-fs SESAM mode-locked Yb, Y: CaF-SrF laser.

We conducted a comprehensive study on the optical spectroscopy properties and laser performances of a Yb, Y: CaF-SrF co-doping mixed crystal. Our investigation included an analysis of the absorption, emission, and gain cross-sections, and we were able to achieve a wide tuning range of 75.4 nm.

Diode-pumped microchip laser from neodymium doped calcium borosilicate glass.

Calcium borosilicate glass doped with 0.6 atomic percent (at.%) of Nd ions (NdCBS06) was fabricated using the high-temperature melting method.

Impact of internal defects on laser-induced damage in Nd, Gd co-doped SrF crystals.

The comprehensive investigation into the distribution characteristics of internal defects across various growth areas of Nd, Gd: SrF (NGSF) crystals is presented in this paper by photothermal weak absorption, stress-induced birefringence, and laser confocal microscopy. The stress-gathering and absorption bands resulting from the accumulation of internal defects predominantly consist of fractures, empty tubes, and inclusions with impurities, as observed through SEM. Furthermore, laser-induced damage characteristics were examined to explore the mechanisms of internal defect-induced damage by a 1064 nm pulsed laser, revealing the exponential-Chapman relationship between weak absorption and laser damage threshold fluence.

Nanosecond laser-induced surface damage growth and its mechanism of single crystal CaF (111) at 193 nm.

The damage growth of calcium fluoride crystal (CaF) induced by 193 nm laser irradiation poses a significant risk to the operation of deep-ultraviolet photolithography. It is crucial to explore the damage growth characteristics and mechanism of CaF crystal induced by a 193 nm laser for the safe operation of integrated photolithography systems. This paper analyzed the trend of 193 nm laser-induced damage growth of CaF crystal surfaces and obtained the damage growth coefficients and thresholds of three CaF crystal test samples.

35-fs diode-pumped mode-locked ytterbium-doped multi-component alkaline-earth fluoride laser.

We demonstrate direct generation of sub-40 fs pulses from a diode-pumped mode-locked laser using an ytterbium-yttrium codoped multi-component alkaline-earth fluoride crystal and a semiconductor saturable absorber mirror. The Yb,Y:(Ca,Sr)F laser delivers soliton pulses as short as 35 fs at 1056.7 nm, with an average output power of 182 mW at a repetition rate of ∼65.

Electron paramagnetic resonance and photoluminescence study on local structure of Gd ions in Gd-doped CaF crystals.

Employing electron paramagnetic resonance (EPR) and excitation and photoluminescence (PL) spectra, changes of the local structure of Gd ions were investigated for the CaF crystals containing 0.00015, 0.17, 1.

Effect of Tm concentration on structure, spectral properties and cross relaxation of Tm:CaF crystal.

Through the investigation of spectral characteristics, the evolution of cluster proportions and the cross-relaxation process in Tm:CaF crystals as a function of Tm doping concentration has been clarified. A quantitative model has been established to describe the relationship between these factors. At low concentrations (0.

Component design and stable SESAM mode-locking of the disorder middle entropy Yb:CaSrBaF single crystal.

To the best of our knowledge, this is the first report on continuous and passively mode-locked operation of the multi-component fluoride CaSrBaF crystal. A novel disorder laser material, Yb:CaSrBaF (CaSrBaF) of multi-component middle entropy crystal was designed and grown by temperature gradient technique (TGT) for the first time. X-ray diffraction (XRD) and X-ray fluorescence (XRF) analysis of Yb:CaSrBaF crystal reveals that Ca, Sr, and Ba of near equal atomic ratio (1:1:1) have formed a homogeneous single-phased fluorite solid solution.

Room-temperature high-power laser emission of erbium-doped fluorite crystals at 2.8 µm.

We report on a high-power continuous-wave (CW) laser at 2.8 µm employing erbium (Er)-doped fluorite crystals as gain materials. With an optimized Er ion concentration, thin "slab" geometry of the sample matching with the tailored pump beam profile and compensated negative thermal lens using a pair of concave mirrors cavity configuration, a highest power of 14.

Femtosecond pulse generation from a SESAM mode-locked Tm,Ho:SrF laser at 2.08 µm.

We report on a passively mode-locked Tm,Ho:SrF laser employing a SESAM as saturable absorber (SA), delivering nearly Fourier-transform-limited 246 fs pulses at 2084nm without any additional intra- or extra-cavity dispersion compensation elements. This represents, to the best of our knowledge, the shortest pulses generated from the mode-locked fluoride bulk lasers in the 2-µm spectral range. Such compact femtosecond laser can be a potential seed source for large-sized fluoride bulk amplifier systems with exact gain match, enabling the generation of ultrashort intense pulses around 2 µm.

All-solid-state 3-µm single-frequency Er:CaF laser with a stable and switchable wavelength.

We have demonstrated a 3-µm all-solid-state single-frequency laser with a stable center frequency and a switchable wavelength using the intra-cavity Fabry-Perot etalon method. Experimentally, the central wavelengths of the laser for the single-longitudinal mode are 2728 and 2794 nm, with maximum output powers of 268 and 440 mW, respectively. The corresponding single-longitudinal mode linewidths are 25 and 11 MHz.

Sub-50-fs Kerr-lens mode-locked Yb-doped fluoride laser with 44% optical efficiency.

Yb-doped fluoride has been demonstrated to be potential crystals for application in efficient ultrafast lasers. However, the trade-off between the shorter pulses with higher efficiencies is a challenge. In this work, using , : crystal, we report on a sub-50-fs Kerr-lens mode-locked oscillator with an optical efficiency up to 44%.

Diode-pumped mode-locked Yb:ScSiO laser generating 38 fs pulses.

We report on sub-40 fs pulse generation from a Yb:ScSiO laser pumped by a spatially single-mode fiber-coupled laser diode at 976 nm. A maximum output power of 545 mW was obtained at 1062.6 nm in the continuous-wave regime, corresponding to a slope efficiency of 64% and a laser threshold of 143 mW.

Diode-pumped SESAM mode-locked Tm:ScSiO laser.

We report a diode-pumped passively mode-locked Tm:ScSiO (Tm:SSO) laser for the first time, to the best of our knowledge. The stable continuous-wave (CW) mode-locking is achieved with a semiconductor saturable absorber mirror (SESAM). Operating at the eye-safe wavelength of 1967.

Sub-60-fs ultralow threshold and efficient Kerr-lens mode-locked Yb,Gd:CaSrF laser.

In this Letter, using a Yb,Gd:CaSrF co-doping mixed crystal, an ultra-low threshold and efficient Kerr-lens mode-locked femtosecond oscillator is realized with a mode-locking threshold as low as 150 mW. With a 200-mW pump power, the shortest pulses are obtained with a pulse duration of 57 fs. A maximum mode-locked output power of 185 mW is observed under a 500-mW pump power, corresponding to an optical-to-optical efficiency of up to 37%.

Laser-diode-pumped Tm:SrF single crystal for high efficiency CW laser operation at ∼2 µm.

A Tm:SrF single crystal is grown by a modified temperature gradient technique (TGT). A study of the fluorescence characteristics and laser performance is carried out. Under laser-diode (LD) end-pumping, a continuous-wave (CW) laser is demonstrated.

Tb,Y:SrF crystal for efficient laser operation in the visible spectral region.

A Tb,Y:SrF crystal with high optical quality is grown using the temperature gradient technique. The spectroscopic and laser properties of the crystal in the visible spectral region are studied. A fluorescence lifetime of 5.

Indium Tin Oxide Nanowire Arrays as a Saturable Absorber for Mid-Infrared Er:CaSrF Laser.

We demonstrated a passively Q-switched Er:CaSrF laser with indium tin oxide nanowire arrays as an optical modulator in the mid-infrared region. In the Q-switched regime, the maximum output power of 58 mW with a slope efficiency of 18.3% was acquired.

Tailoring local coordination structure of the Er ions for tuning the up-conversion multicolor luminescence.

The regulation of the local structure around Er ions is an important channel for adjusting the characteristic of up-conversion luminescence. In this paper, the cubic-phased Er:CaF crystals with different Er doping concentrations were fabricated with temperature gradient technique (TGT) method and the effect of the local coordination structure of the Er ions on its luminescence performance was investigated. The local coordination structure of Er ions was simulated by density functional theory.

Irreversible accumulated SERS behavior of the molecule-linked silver and silver-doped titanium dioxide hybrid system.

In recent years, surface-enhanced Raman scattering (SERS) of a molecule/metal-semiconductor hybrid system has attracted considerable interest and regarded as the synergetic contribution of the electromagnetic and chemical enhancements from the incorporation of noble metal into semiconductor nanomaterials. However, the underlying mechanism is still to be revealed in detail. Herein, we report an irreversible accumulated SERS behavior induced by near-infrared (NIR) light irradiating on a 4-mercaptobenzoic acid linked with silver and silver-doped titanium dioxide (4MBA/Ag/Ag-doped TiO) hybrid system.

High-efficiency ∼2 µm CW laser operation of LD-pumped Tm:CaF single-crystal fibers.

The Tm:CaF single-crystal fibers were successfully grown by modified temperature gradient technique method. The J-O intensity parameters, spontaneous radiative transition rates, radiative lifetimes and fluorescence branching ratios of Tm were calculated with Judd-Ofelt theory. A systematic study of the fluorescence characteristics has been carried out.

Continuous-wave and Q-switched Nd:BGSO lasers based on bismuth nanosheets absorber.

This Nd:BGSO (Nd:BGSO) crystal was grown using the micro-pulling-down method, and the continuous-wave laser operation of this crystal was demonstrated for the first time, to the best of our knowledge. The maximum output power of 1.038 W was obtained under the absorbed pump power of 3.

Active Q-switching operation of slab Ho:SYSO laser wing-pumped by fiber coupled laser diodes.

In this paper, we demonstrate the continuous-wave and acousto-optical Q-switched performance of diode-pumped slab Ho:(ScY)SiO (Ho:SYSO) laser at 2.1 µm for the first time. Two 1.

Efficient Ho:(ScY)SiO laser at 2.1 µm in-band pumped by Tm fiber laser.

In this paper, we demonstrate a new 2.1-µm Ho:(ScY)SiO (Ho:SYSO) laser at room temperature. The absorption and emission spectra of Ho:SYSO crystal were studied at temperature of 300 K.