In this work we present a compact, nanosecond pulsed, single frequency, single stage Yb-doped fiber amplifier by using an overall fiber core diameter of 20 μm. The key component is a custom made, compact, ultra-low noise, single frequency ring-cavity solid state laser (SSL) at 1064 nm used as a master oscillator. The SSL can be designed to provide nanosecond pulses with pulse energies in the sub-mJ range. Our ultimate goal is to develop a compact linearly polarized, single frequency, nanosecond pulsed laser source in an all-fiber format. Short (less than 1m), highly Yb-doped fibers have been used in order to suppress non-linear effects.

We demonstrate that both direction and extinction ratio of the polarization in an Yb:KGW laser can be arbitrarily controlled using conical refraction. No additional components are necessary. Output power was 8.6W and slope efficiency 60.5%.

Laser Induced Fluorescence (LIF) could permit fast early warning systems either for point or stand-off detection if a reliable classification of warfare biological agents versus biological or non-biological fluorescing background can be achieved. In order to improve LIF discrimination capability, a new system is described in which the fluorescence pattern is enriched by the use of multiple wavelength delayed excitation while usual spectral fluorescence analysis is extended to time domain to use both aspects as criteria for classification. General considerations and guidelines for the system design are given as well as results showing good discrimination between background and simulants.

We report on a volume-Bragg-grating tunable Yb:KYW laser. By using s-polarized light on the grating, we obtain an output power of 3 W in a single beam, doubled compared to earlier p-polarization results. The laser tunability was from 996 nm to 1048 nm. Detailed measurements of the laser spectrum revealed a bandwidth of 10 GHz.

The use of solid-state lasers as excitation sources in bioanalytical instrumentation technology, as alternatives to gas lasers, has grown increasingly popular over the last few years.The reasons are a multitude of advantages in comparison to gas lasers, such as compact size, less heat generation and power consumption, no vibrations or noise, high beam stability and longer lifetime.

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.

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.

We present a theoretical model describing finite beams incident at volume Bragg gratings and confirm it experimentally. Reflectivity decreases with increasing incidence angle and decreasing beam size, and the transmitted transversal mode profile is transformed.

Energy transfer and spectroscopic properties at high temperatures have been investigated in Er,Yb:YAG crystals. It is shown that at elevated temperatures around 600–800°C these characteristics become similar to those in the efficient 1.5μm laser medium – Er,Yb-doped phosphate glasses.

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.

Using internal conical refraction, we demonstrate an Yb:KGW laser where the polarization state can be arbitrarily altered without any additional cavity components. The extinction ratio can also be altered between 1:1 and 40:1. The maximum output power achieved was 8.6 W at a slope efficiency of 60.5% with respect to incident pump power. This equals the power performance of a standard Yb:KGW laser used for reference.

We demonstrate a tunable Yb:KYW laser, locked by a volume Bragg grating in a retroreflector geometry. The power was ~1 W within the tuning range from 1032 nm to 1048 nm.

A study of Yb:GdCOB under diode-bar pumping has been performed and the results are compared, experimentally and theoretically, with Yb:KGW in the same cavity. An output power of 7.3 W and a slope efficiency of 57.4% were obtained. Self-frequency-doubling experiments are also discussed.

We demonstrate a technique for laser tuning based on a volume Bragg grating. A peak power of 4.7 W, a bandwidth <0.1 nm and a 1000-1050 nm tuning range is achieved in an Yb:KYW laser.