Microlenses, microlens arrays, and diffractive optics are used in medical applications for homogenization of laser beams for laser eye surgery and aesthetic skin treatment, for creating multi-spot arrays for ophthalmic diagnostics, for collimating and shaping laser beams for surgical applications, and for imaging applications such as optical coherence tomography and scanning confocal microscopy.
Recent advances in near infrared (NIR) and mid-wavelength infrared (MWIR) quantum cascade and fiber lasers in conjunction with new diagnostic and treatment approaches are placing new demands on microoptics for these applications. These needs include a broad NIR - MWIR transmission, high numerical aperture (NA), and small form factor for minimally invasive applications. With 15 years of experience, Jenoptik's Grayscale lithographically fabricated gallium phosphide (GaP) microlenses and microlens arrays meet these demands with:
1) A unique and broad wavelength range from 600 nanometers to beyond 5 mikrometers
2) A high refractive index of 3.1 allowing a single element lens or lens array with NA's up to 0.85
3) Complex surface shapes providing for beam collimation and circularization of high divergence diode lasers with a single element
Scanning confocal microscopy and minimally invasive optical coherence tomography are two examples where a single GaP microlens or microlens array can be used to extend the wavelength range over traditional GRIN and Si lenses. Jenoptik's ability to fabricate complex aspheric elements with high numerical aperture also provide for better imaging performance when compared with GRIN lens based systems.
In addition, standard manufacturing processes are available for a range of different optical materials such as SiO2, GaAs, CaF2, Al2O3, ZnS, ZnSe, Ge, and chalcogenide glass.
Source: JENOPTIK Optical Systems GmbH