Ulrich Steegmueller

Green semiconductor disk laser with 0.7W cw output power

We demonstrate 0.7W cw output power at 520nm from an intracavity frequency doubled optically pumped semiconductor disk laser at room temperature. High beam quality and optical conversion efficiency of 10% has been achieved.

Progress in ultra-compact green frequency doubled optically pumped surface emitting lasers

Compact, stable and efficient green lasers are of great interest for many applications like mobile video projection, sensing, distance measurement and instrumentation. Those applications require medium values of output power in the 50mW range, good wall-plug efficiency above 5 % and stable operation over a wide temperature range. In this paper we present latest results from experimental investigations on ultra-compact green intracavity frequency doubled optically pumped semiconductor InGaAs disk lasers. The green laser setup has been limited to a few micro optical and semiconductor components built on a silicon backplane and fits within an envelope of less than 0.4 cc. An optical frequency looking scheme in order to fix the fundamental wavelength over varying operating conditions like changing output power and ambient temperature has been applied. The cavity has been optimized for fast modulation response and high efficiency using quasi-phase matching non-linear material. Recent data from cw and high-frequency characterization is presented.

Highly reliable and efficient laser bars and cost efficient packaging

High power diode lasers convince by their very efficient conversion of electrical into optical energy. Besides high efficiencies and record absolute power levels, reliability in all possible operation modes and cost become increasingly important. We present diode laser bars in the 940nm range with wall plug efficiencies of about 65% at an emission power of 100W and with excellent reliability. The test had been performed on a stack with 5 bars at an output power of 100W per 1cm bar and after about 4000hrs test time, lifetimes of more than 40 000hour were estimated. The efficiency of these bars was at the beginning and at the end of this test about 65%. Operation modes between cw operation and q-cw (200μsec pulses) were evaluated and it will be shown, that pulses in the range of 1Hz are the hardest conditions, which can cause catastrophic failures. Using submounts with matched thermal expansion coefficient, this failure was prevented and lifetimes similar to cw-operation were reached. In order to reduce costs of laser power, we developed a laser package that offers high power at good reliability and provides a collimated beam for about 5

High-performance at low cost: the challenge manufacturing frequency doubled green semiconductor lasers for mass markets

/W, as a cost target in mass production conditions. This was achieved by using packaging concepts that were developed for high power semiconductor devices. These results will further enhance the applicability of diode lasers in industrial application.

3.5: Late-News Paper: RGB Laser for Mobile Projection Devices

Laser projection arising as a new application in the consumer market has been the driving force for OSRAM Opto Semiconductors to develop a frequency doubled semiconductor laser and the production technology necessary to make the complexity of an advanced laser system affordable. Optically pumped frequency doubled semiconductor lasers provide an ideal platform to serve the laser projection application. Based on this scalable technology, we developed a 50 mW green laser comprising all the properties that can be expected from a high performance laser: Excellent beam quality and low noise, high speed modulation, good efficiency and long life time. More than that, the package is very compact (<0.4 cm3) and may be operated passively cooled at up to 60°C. Managing lasing wavelength and controlling phase matching conditions have been major design considerations. We will describe the key characteristics of the green laser, and will also present results from reliability testing and production monitoring.

0.7W Green Frequency Doubled Semiconductor Disk Laser

Recent advances in small form factor lasers for mobile projection devices are discussed. Based on semiconductor solutions, efficient and very compact full color laser modules are realized, suitable both for imager and scanning beam type laser projection systems.

67.3: Progress in Small‐Form‐Factor Lasers for Projection Displays

We demonstrate 0.7W cw output power at 520nm from an intracavity frequency doubled Optically Pumped Semiconductor Disk Laser at room temperature. High beam quality and optical conversion efficiency of 10% has been achieved.

Optical encoder with triple photodiode

Prospects of red, green and blue lasers as light source for laser displays are discussed. Recent progress on semiconductor based red, green and blue lasers may enable very compact scanning beam laser displays for mobile applications. For larger screen displays, lasers are employed as illumination source for imager based projection engines.