Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Widely tunable cavity-enhanced backward difference-frequency generation

Ming-Yuan Gao, Yue-Wei Song, Ren-Hui Chen, Yin-Hai Li, Zhi-Yuan Zhou, Bao-Sen Shi

Abstract

Difference-frequency generation (DFG) is a powerful technique for generating widely tunable infrared radiation. However, conventional phase-matching schemes may require tuning multiple parameters-such as the wavelengths, crystal temperature, crystal angle, and poling period-to achieve wide tunability, which increases the complexity of practical operation. In this work, we employ a backward quasi-phase-matching scheme with distinctive tuning characteristics and demonstrate pump-enhanced continuous-wave DFG output tunable from 1751 nm to 2451 nm (700 nm range) in a bulk crystal. The tuning is achieved solely by varying the pump wavelength and the signal wavelength (less than 5 nm), enabling continuous, rapid, and room-temperature operation. The tuning characteristics, power-scaling behavior, and output stability are experimentally verified with the idler wavelength set at 2000 nm. The approach offers a new paradigm for widely tunable infrared radiation generation and holds promise for applications in spectroscopy and biomedical sensing.

Widely tunable cavity-enhanced backward difference-frequency generation

Abstract

Difference-frequency generation (DFG) is a powerful technique for generating widely tunable infrared radiation. However, conventional phase-matching schemes may require tuning multiple parameters-such as the wavelengths, crystal temperature, crystal angle, and poling period-to achieve wide tunability, which increases the complexity of practical operation. In this work, we employ a backward quasi-phase-matching scheme with distinctive tuning characteristics and demonstrate pump-enhanced continuous-wave DFG output tunable from 1751 nm to 2451 nm (700 nm range) in a bulk crystal. The tuning is achieved solely by varying the pump wavelength and the signal wavelength (less than 5 nm), enabling continuous, rapid, and room-temperature operation. The tuning characteristics, power-scaling behavior, and output stability are experimentally verified with the idler wavelength set at 2000 nm. The approach offers a new paradigm for widely tunable infrared radiation generation and holds promise for applications in spectroscopy and biomedical sensing.
Paper Structure (1 section, 4 equations, 4 figures, 1 table)

This paper contains 1 section, 4 equations, 4 figures, 1 table.

Table of Contents

  1. Data Availability Statement

Figures (4)

  • Figure 1: (a) Experimental setup. EOM: electro-optic modulator; M0: mirror; M1-M4: cavity mirrors; L: lens; PD: photodetector; PZT: piezoelectric transducer; PPKTP: periodically poled KTP crystal; DM: dichroic mirror; BF: bandpass filter; PM:power meter. (b) Reflection spectrum of the cavity at a pump wavelength of 873.8 nm, recorded on an oscilloscope during cavity-length scanning.
  • Figure 2: (a) Wavelength tuning and (b) temperature tuning measurements of the DFG output. The data are fitted with ${sin}{c^2}$ functions.
  • Figure 3: Idler power as a function of (a) signal power and (b) pump power. Solid lines indicate simulation results. In (a), the pump power was fixed at 250 mW. In (b), the signal power was fixed at 3 W.
  • Figure 4: (a) Idler power at 2000 nm measured over 40 minutes. The peak-to-peak power stability is 3.6%. (b) Idler output across the 1751–2451 nm range. The pump and signal powers are fixed at 250 mW and 3 W, respectively. The solid line represents the simulation result.