We report on Doppler-free laser spectroscopy in a Cs vapor cell using a dual-frequency laser system tuned on the Cs D line. Using counter-propagating beams with crossed linear polarizations, an original sign reversal of the usual saturated absorption dip and large increase in Doppler-free atomic absorption is observed. This phenomenon is explained by coherent population trapping (CPT) effects. The impact of laser intensity and light polarization on absorption profiles is reported in both single-frequency and dual-frequency regimes. In the latter, frequency stabilization of two diode lasers was performed, yielding a beat note fractional frequency stability at the level of 3×10 at 1 s averaging time. These performances are about an order of magnitude better than those obtained using a conventional single-frequency saturated absorption scheme.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1364/OL.41.002982 | DOI Listing |
A multi-wavelength mode-locked fiber laser can generate different wavelengths from a single laser cavity, offering potential as a dual-frequency comb and serving as an ideal light source for terahertz wave generation. We present an optimized hybrid mode-locked Er-doped fiber laser with flexible outputs: switchable and tunable dual-wavelength mode-locking, along with stable tri-wavelength mode-locking, which is achieved by introducing 0.69 m polarization-maintaining fiber and bent 200 m single-mode fiber to enhance intra-cavity birefringence and nonlinear effect to optimize the hybrid mode-locking effect, that is, build the composite filter effect.
View Article and Find Full Text PDFZhonghua Nei Ke Za Zhi
October 2024
Department of Interventional and Minimally Invasive Oncology Therapy, the Second Hospital of Shandong University, Qilu Medical College, Shandong University, Jinan 250033, China.
To evaluate the safety and efficacy of percutaneous transhepatic papillary balloon dilation (PTPBD) combined with flexible ureteroscopy-guided dual-frequency double-pulse ND:YAG (FREDDY) laser lithotripsy (PTPBD-FREDDY) for the treatment of giant (>1.5 cm diameter) common bile duct stones. A retrospective analysis was conducted on 26 patients with large-diameter difficult choledocholithiasis admitted to two medical centers from December 2017 to October 2021.
View Article and Find Full Text PDFAnal Chem
September 2024
School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian, Liaoning 116024, China.
To achieve high sensitivity detection of dual-component greenhouse gases carbon dioxide and methane simultaneously, a multimechanism synergistic enhanced all-optical photoacoustic spectroscopy gas analyzer is presented. The acoustic resonance of the photoacoustic cell and the mechanical resonance of a fiber-optic cantilever acoustic sensor are used to enhance the photoacoustic signals of the dual-component gas. The optimized multipass beam reflection structure enhances the effective excitation power of the dual-component gas.
View Article and Find Full Text PDFPreviously, we have proposed a method to control the emission spectrum of the vertical-cavity surface-emitting laser (VCSEL) with the synchronized modulation of the injection current at single and doubled frequencies. In this work, the above method is used to improve the metrological characteristics of the coherent population trapping (CPT) resonance in Rb. The dual-frequency (DF) modulation reduces the carrier power and suppresses the light shift of the resonance frequency, if it is unattainable with the single-frequency modulation.
View Article and Find Full Text PDFObjective: To investigate the clinical effects of new fiberoptic cholangioscopy-guided percutaneous transhepatic choledochoscope lithotomy (PTCSL) combined with dual-frequency laser lithotripsy for the treatment of intractable hepatolithiasis.
Methods: Eighty patients with intractable hepatolithiasis who received treatment in the Second Hospital Affiliated to Zhejiang University School of Medicine from December 2020 to December 2022 were grouped according to the surgical methods. Forty-two patients who received hepatectomy were divided into the control group, 38 patients who received new fiber-optic choledochoscope-guided PTCSL combined with dual-frequency laser lithotripsy were divided into the observation group, and the treatment results of the two groups were compared.
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!