September 2015 (Volume 29)

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Norlase – a Danish company headquartered in Roskilde and founded in January 2014 – has developed a new class of visible laser based on patented tapered diode double laser technology (TDDL). This latest laser technology has been incorporated into AuroraOne (a new laser head product) to record a Denisyuk hologram.

Norlase
Reflection hologram of a Lego character recorded using Norlase AuroraOne 515nm laser head

The company is a university spinout from the Technical University of Denmark and has grown to a team of 15 people in just 18 months. The team – comprising photonics scientists, academics and industry advisors to develop and market the next generation of visible lasers – was put together by CEO aand co-founder Peter Skovgaard. Prior to this, he successfully headed product development teams at Crystal Fibre, NKT Photonics and Kaleido Technologies.

Holography News® ‘caught up’ with Nicklas Jarnel (Business Developer) and Dr Michelle Stock (Director of Business Development) from Norlase following the 10th International Symposium on Display Holography in St Petersburg, in July, where Norlase’s technology and future
developments were presented.

Innovative laser technology

Many technologies exist to make continuous wave (CW) near-diffraction limited visible light lasers. These range from cheap, low power (typically 0.5 watt) and reliable laser diodes for use in, for example, DVD players up to powerful (hundreds of watts), large, costly and
complex lasers used for cutting steel or for military applications. These latter high power applications use diode pumped solid state lasers (DPSS), optically pumped semi-conductor lasers (OPSL) lasers or fibre laser technologies. However, the problem for a lot of applications, especially in medicine and also for holography, are that visible light lasers with a power range between 1-20 watts are required. One approach to solving this problem is to scale down the large complex DPSS lasers, but cost and laser reliability can become an obstacle. To solve this problem, Norlase developed an innovative patented solution using tapered diode double laser technology. This technology uses simple laser diodes operating in the non-visible infra-red wavelength range, and changes the output wavelength using a frequency converting crystal without losing laser power or beam quality. The result is a new class of lasers with power levels in the 1-20 watt region that have a simpler architecture, are cheaper, and have an exceptional beam quality compared to the alternative laser systems.

According to Norlase the advantages of the TDDL compared to DPSS lasers are:

  • Wavelengths between 460-590 nanometres (nm) are possible;
  • Higher laser efficiencies;
  • Stable and reliable laser beams;
  • Lower costs; and
  • Smaller footprint devices.

The first product developed by Norlase using TDDL technology is the AuroraOne laser head that is air cooled and with a small footprint of 140mm x 88.9mm x 50mm. Different wavelengths are possible that include blue lasers at 465nm and 488nm and green lasers 515nm and
532nm, with power levels up to 4 watts.

Tapered double-diode laser technologies for hologram use

One of the first applications for the AuroraOne was to produce a reflection hologram of an Olympic coin using the Denisyuk holographic recording method. An AuroraOne 488nm laser head was used, employing Litiholo RT20 holographic film and an exposure time of approximately 100 seconds.

Further holograms have also been produced using a Norlase AuroraOne 532nm laser for example, Lego® characters.

Markets and applications

Aside from holography, the main market for Norlase is the pump laser market, where the low noise AuroraOne laser is an enabling component for titanium/sapphire lasers, and can strongly enhance their use for eye diagnostics, for instance via optical coherence tomography.

Other applications and markets include:

  • DNA sequencing – where blue laser light(488nm) can be used to deliver ultra-fast sequencing;
  • Medical – AuroraOne lasers deliver highpower and high beam-quality in exactly the wavelengths best suited for specific
    treatments that enables more convenient and effective laser treatment systems. Applications include dermatology,
    ophthalmology treatments, as well as medical imaging;
  • Laser spectroscopy – where green (532 nm) lasers can be used for conducting Raman spectroscopy or for efficiently
    pumping titanium/sapphire lasers.Future developments are mainly focused on finding markets for new wavelengths, plus further development of the Norlase impressive product portfolio.www.norlase.com