Björn Jacobsson

Narrowband bulk Bragg grating optical parametric oscillator

A narrowband, pulsed optical parametric oscillator (OPO) whose output coupler is a bulk glass Bragg grating is demonstrated. The OPO is based on periodically poled KTiOPO4 and is pumped by a pulsed, frequency-doubled Nd:YAG laser at 532 nm, generating a signal at 975 nm with a total efficiency of 35%. This novel and compact device shows a spectral bandwidth of 0.16 nm (50 GHz), a decrease by a factor of 20 compared with that when a conventional mirror is used. By using a folded cavity, we demonstrate tunable radiation with a tuning range of 60 nm and maintained spectral bandwidth.

Single-longitudinal-mode Nd-laser with a Bragg-grating Fabry-Perot cavity

We demonstrate 0.85 W of power in a single longitudinal mode at 1066 nm from a Nd:GdVO(4) laser. The laser consists of only two components, the gain medium and a volume Bragg grating in glass, in a simple linear cavity comprising a combination of a Fabry-Perot cavity and a narrowband filter. Thanks to the narrowband Bragg grating, the single longitudinal mode is maintained for a cavity length up to 8 mm, while a continuous tuning of 25 GHz is achieved for a shorter cavity and lower power.

Tunable single-longitudinal-mode ErYb:glass laser locked by a bulk glass Bragg grating.

A single-longitudinal-mode ErYb:glass laser with a linewidth of 90 kHz is demonstrated by locking the laser wavelength to 1552.6 nm with a bulk glass Bragg grating. Using a piezoelectric actuator, the wavelength could be tuned over a range of 0.25 nm (31 GHz) in steps of 17 pm (2.1 GHz), with an output power of a few milliwatts.

Widely tunable Yb:KYW laser with a volume Bragg grating.

We demonstrate a narrowband, continuously tunable Yb:KYW laser locked by a volume Bragg grating at oblique incidence in a retroreflector configuration. The tuning range was 997 nm to 1050 nm (15 THz) with bandwidth < 0.1 nm and a maximum output power of 4.7 W. In a high-quality beam with M(2) < 1.3, the maximum output power was 1.7 W. We also demonstrate 3 W output power at 1064 nm from the same Yb:KYW laser with the grating at normal incidence.

Finite Beams in Reflective Volume Bragg Gratings: Theory and Experiments

We present a theoretical model to describe finite beams incident on reflective volume Bragg gratings. We also give experimental results that verify our model. From these results, we identify certain properties of reflective volume Bragg gratings, such as beam waist, incidence angle and beam profile, that have direct impact on the design of laser cavities that include such gratings. We also show how these gratings can act as spatial mode filters.

Tunable narrowband optical parametric oscillator using a transversely chirped Bragg grating

We demonstrate a novel technique for locking and tuning of a near-degenerate nanosecond optical parametric oscillator (OPO) using a transversely chirped volume Bragg grating. When the grating was translated, the OPO signal wavelength could be tuned from 1011 to 1023 nm (3.5 THz). The OPO was based on a periodically poled KTiOPO(4) as a nonlinear crystal and was pumped at 532 nm with up to 1.9 mJ of energy. The generated signal at an energy of 0.37 mJ had a bandwidth of 0.50 nm and a suppression of broadband background of >30 dB. The demonstrated technique is widely applicable for the construction of narrowband tunable sources.

Quasi-two-level Yb:KYW laser with a volume Bragg grating

Using a volume Bragg grating as input coupler, we demonstrate an Yb:KYW laser with a very small quantum defect (1.6%) and an output power of 3.6 W. The laser was longitudinally diode-pumped at 982 nm and the laser wavelength was determined by the grating to 998 nm, with a laser bandwidth of 10 GHz (33 pm). Due to the low quantum defect, the laser should be readily scalable to 20 W or more without critical thermal effects.

Narrowband and tunable ring optical parametric oscillator with a volume Bragg grating

We demonstrate a new technique for locking and narrowing the wavelength of a ring optical parametric oscillator with a volume Bragg grating at an angle in a retroreflector design.

Characterization of a liquid-xenon-jet laser-plasma extreme-ultraviolet source

A liquid-xenon-jet laser-plasma source for extreme-ultraviolet (EUV) and soft-x-ray generation has been characterized. Being a source candidate for EUV lithography (EUVL), we especially focus on pa ...

Monolithic Bragg-locked Nd:GdVO4 laser.

We present a monolithic single-longitudinal-mode laser based on Nd:GdVO(4) and a volume Bragg grating. The laser at 1066 nm had a bandwidth below 40 MHz at a power of 30 mW. With temperature, the laser frequency could be continuously tuned without mode hops over a range of 80 GHz. The demonstrated laser design is very compact and simple and can be used to lock the laser wavelength anywhere in the gain spectrum.