High-power CW single-frequency Nd:YVO₄/LBO laser quasi-continuously tuneable over a wide frequency range

Abstract

In this work, we present for the first time a method for quasi-smooth tuning of the second harmonic radiation of an Nd:YVO 4 /LBO laser within a 60-GHz range. Practicality of this method is demonstrated at the radiation output power of 1.5 W at 532 nm. The proposed method features automatic stitching of 12-GHz continuously tuneable ranges to the precision of the laser output line width (5 MHz). The stitching does not require a precision wavelength meter and is based on a high-finesse scanning confocal interferometer.

240-GHz continuously frequency-tuneable Nd:YVO_4/LBO laser with two intra-cavity locked etalons

“…Therefore, the entire smooth scanning range achieved for the second harmonic radiation is 240-GHz wide and consists of 17 spectrally stitched individual continuous tuning ranges with the average width of ~14.5 GHz. It is pertinent to note that the term "generation frequency tuning" used in numerous publications on single-frequency Nd:YVO 4 lasers [9][10][11][12][13][14][15][16] does not always imply smooth adjustment of the laser's output frequency. This term may refer, for instance, to the possibility of setting any (or a specific) wavelength within the specified spectral range.…”

“…This term may refer, for instance, to the possibility of setting any (or a specific) wavelength within the specified spectral range. Generally, this does not preclude mode hopping in the process of frequency tuning [12,[14][15][16] and furthermore does not guarantee automatic continuous or quasi-continuous scanning of the generation frequency over the entire specified spectral range.…”

“…Continuous generation frequency tuning in Nd:YVO 4 /NC lasers over ranges exceeding the FSR of the laser cavity was earlier reported in various publications where the following continuous frequency tuning ranges of the second-harmonic radiation (532 nm) at the specified output power were demonstrated: 6.4 GHz @ 18 W [8], 8.2 GHz @ 12 W [8], 17 GHz @ 200 mW [9], 17.2 GHz @ 480 mW [10], 24 GHz @ 10.5 W [11], 60 GHz @ 1.5W [12]. Continuous (without mode hopping) tuning of the fundamental harmonic frequency in Nd:YVO 4 lasers was previously achieved in the ranges 2.9 GHz [13], and 107 GHz @ 103 mW [2].…”

“…Continuous (without mode hopping) tuning of the fundamental harmonic frequency in Nd:YVO 4 lasers was previously achieved in the ranges 2.9 GHz [13], and 107 GHz @ 103 mW [2]. All the work quoted in this paragraph (except [12]) featured continuous frequency tuning of Nd:YVO 4 /NC lasers in a single smooth frequency scanning range, not relying on methods for stitching several such ranges into one.…”