Dual-wavelength vortex beam with high stability in a diode-pumped Yb:CaGdAlO4 laser. (26th March 2018)

• Record Type: Journal Article
• Authors: Shen, Yijie; Meng, Yuan; Fu, Xing; Gong, Mali
• Is Part Of: Laser physics letters. Volume 15:Number 5(2018:May)
• Publication Date: 2018-03-26
• Subjects: solid-state lasers -- dual-wavelength spectra -- orbital angular momentum -- optical vortices; Lasers -- Periodicals; Physics -- Periodicals; 621.366
• DOI: 10.1088/1612-202X/aaaa97
• Languages: English
• ISSNs: 1612-2011

Abstract

Abstract: We present a stable dual-wavelength vortex beam carrying orbital angular momentum (OAM) with two spectral peaks separated by a few terahertz in a diode-pumped Yb:CaGdAlO4 (CALGO) laser. The dual-wavelength spectrum is controlled by the pump power and off-axis loss in a laser resonator, arising from the broad emission bandwidth of Yb:CALGO. The OAM beam is obtained by a pair of cylindrical lenses serving as a π / 2 convertor for high-order Hermite–Gaussian modes. The stability is verified by the fact that a 1 ħ OAM beam with two spectral peaks at 1046.1 nm and 1057.2 nm (3.01 THz interval) can steadily operate for more than 3 h. It has great potential for scaling the application of OAM beams in terahertz spectroscopy, high-resolution interferometry, and so on.