Jason P. Watson

Visible laser and laser array sources for projection displays

Laser-based projection displays have long attracted interest because of the multiple advantages (expanded color gamut, high resolution, longer lifetime, etc.) expected from lasers as compared to lamps. However, most of these advantages have been largely negated by the significant cost, size, and cooling requirements associated with lasers, and their inability to produce red, green, and blue colors in the same platform. In this paper, we review a new, laser array technology based of frequency-doubled, semiconductor, surface-emitting lasers. The key features of this technology, such as demonstrated multi-Watt output for rear-projection TVs, power levels scalable with the number of emitters, speckle suppression due to multi-emitter array, and a low-cost and compact design are discussed in detail.

532-nm laser sources based on intracavity frequency doubling of extended-cavity surface-emitting diode lasers

We introduce a novel type of cw green laser source, the Protera 532, based on the intracavity frequency doubling of an extended-cavity, surface-emitting diode laser. The distinguishing characteristics of this platform are high compactness and efficiency in a stable, single-longitudinal mode with beam quality M2 < 1.2. The laser design is based on the previously reported NECSEL architecture used for 488nm lasers, and includes several novel features to accommodate different types of nonlinear optical materials. The infrared laser die wavelength is increased from 976nm to 1064nm without compromising performance or reliability. The intracavity frequency doubling to 532nm has been demonstrated with both bulk and periodically poled nonlinear materials, with single-ended cw power outputs of greater than 30 mW.

High-power high-brightness 980-nm lasers based on the extended cavity surface emitting lasers concept

We describe design and performance of novel, electrically pumped, vertical compound cavity semiconductor lasers emitting at 980 nm. The laser combines a vertical cavity semiconductor laser with a partially reflecting output coupler and an external cavity for mode control. The concept is scalable and has been demonstrated in monolithic low power (few miliwatts) devices all the way to high power extended cavity devices which generate over 950 mW CW multimode power and 0.5 W CW power in a TEM00 mode, the latter with 90% coupling efficiency into a single mode telecommunication fiber. The concept has been applied to the development of uncooled lasers, mounted in TO-56 cans, capable of producing 50 to 100 mW of fiber-coupled power. We have also demonstrated the extended cavity lasers at wavelengths of 920 nm and 1064 nm. We present reliability data for the chips used in the extended cavity lasers.

Laser sources at 460 nm based on intracavity doubling of extended-cavity surface-emitting lasers

Laser sources emitting at 460nm have been developed through intracavity doubling of an extended cavity, surface emitting semiconductor laser. These lasers are compact, spectrally pure, efficient, and have a high quality beam. The basic design is similar to previously reported work[1] at 488nm using Novalux Extended Cavity Surface Emitting Laser (NECSEL) structures. The choice of nonlinear material was found to be critical, with periodically poled materials providing distinct benefits over bulk materials. Output powers exceeded 20mW. The reliability of the completed lasers was found to be excellent.

Development of compact blue-green lasers for projection display based on Novalux extended-cavity surface-emitting laser technology

Compact and efficient blue-green lasers have been receiving increasing interest in the last few years due to their applications in various industries: bio-instrumentation, reprographics, microscopy, etc. We report on the latest developments in frequency-doubled, compact blue-green lasers, based on Novalux extended-cavity surface emitting laser (NECSEL) technology. This discussion will touch upon using NECSEL technology to go beyond a 5-20 milliwatt cw laser design for instrumentation applications and obtain a compact design that is scalable to higher power levels in an array-based architecture. Such a blue-green laser array platform can address the needs of laser light sources in the projection display consumer electronics markets, particularly in rear-projection televisions.

Novel 980-nm and 490-nm light sources using vertical cavity lasers with extended coupled cavities

We have developed novel electrically pumped, surface-emitting lasers emitting at 980 nm with an extended coupled cavity. The concept is scalable from monolithic low power devices all the way to high power extended cavity lasers. The latter have demonstrated 1W cw multi-mode and 0.5 W cw in a TEM00 mode and a single frequency, with 90% coupling efficiency into a single-mode fiber. By inserting a nonlinear optical medium in the external cavity, efficient and compact frequency doubling has been achieved with CW output powers 5-40 mW demonstrated at 490 nm. The latter devices are especially noteworthy due to their very low noise, sub 10 μrad beam pointing stability combined with small size, low power consumption and high efficiency.

490-nm coherent emission by intracavity frequency doubling of extended cavity surface-emitting diode lasers

We describe a novel blue-green laser platform, based on the intracavity frequency doubling of Novalux Extended Cavity Surface Emitting Lasers. We have demonstrated 5 to 40mW of single-ended, 488nm, single-longitudinal mode emission with beam quality M2<1.2. The optical quality of these lasers matches that of gas lasers; their compactness and efficiency exceed ion, DPSS, and OPSL platforms. These unique properties are designed to serve diverse instrumentation markets such as bio-medical, semiconductor inspection, reprographics, imaging, etc., and to enable new applications. We also present data on the reliability of this novel laser platform and its extensions to different wavelengths (in particular, 460nm and 532nm) and to next-generation, highly compact, monolithic intracavity-doubled lasers.

Novel 980-nm and 490-nm light sources using vertical-cavity lasers with extended coupled cavities

We have developed novel electrically pumped, surface-emitting lasers emitting at 980 nm with an extended coupled cavity. The concept is scalable from monolithic low power (~10 mW) devices all the way to high power extended cavity lasers. The latter have demonstrated ~1 W cw multi-mode and 0.5 W cw in a TEM00 mode and a single frequency, with 90% coupling efficiency into a single-mode fiber. By inserting a nonlinear optical medium in the external cavity, efficient and compact frequency doubling has been achieved with CW output powers 5-40 mW demonstrated at 490 nm. The latter devices are especially noteworthy due to their very low noise (0.05% rms from dc-2 MHz), sub 10 mrad beam pointing stability combined with small size, low power consumption (<10 W) and high efficiency.

High-brightness 980-nm pump lasers based on the Novalux extended cavity surface-emitting laser (NECSEL) concept

We describe design, fabrication and performance of novel, electrically pumped, vertical compound cavity InGaAs lasers emitting at 980 and 920 nm. The concept is scalable and has been demonstrated using monolithic low power (~10 mW) devices all the way to high power extended cavity devices which have demonstrated 1 W cw multi-mode and 0.5 W cw in a TEM00 mode and a single frequency, with 90% coupling efficiency into a single-mode fiber. We also describe uncooled vertical compound cavity lasers in TO-56 can packages which produce 50-100 mW of fiber coupled power. Finally, recent developments in intracavity frequency doubling are summarized.

915 nm laser bar-based high-performance sources for fiber laser pumping

Fiber lasers have made significant progress in terms of power output, beam quality and operational robustness over the past few years. Key to this progress has been advances in two technologies - fiber technology and 9xx nm diode laser pump technology based on single emitters. We present the operational characteristics of our new high brightness 9xx nm fiber laser pump sources based on diode laser bars and diode laser bar arrays and discuss the design trade offs involved for realization of devices focused on this application. These trade offs include achieving the lowest slow axis divergence while maintaining high wall plug efficiency and minimizing facet power density to maximize reliability.