Next OSSC Meeting
16 June 2021
6:00 to 6:45 PM
OSSC Annual Business Meeting &
Election of New Officers
No fee for this on-line webinar.
Login credentials will be e-mailed
June 16, 2021
Recent OSSC Meeting
OSSC Online Webinar
Wednesday June 9, 2021, 7:00pm
“Versatile Diffractive Flat Optics”
Prof. Rajesh Menon,
Dir. Lab. for Optical Nanotechnologies
Univ. Utah, Salt Lake City
Traditional refractive lenses are bulky owing to their curvature. Flat diffractive lenses can overcome this difficulty, but traditional diffractive optics have limited reach, primarily due to chromaticity. Recently, we have shown that by treating the “imaging” phenomenon as simply information transfer from the object to the image plane, the spatial distribution of the phase in the focal plane can be an arbitrary function.
Using this concept, we have shown that allowing the phase in the image plane of a flat lens to be a free parameter enables imaging properties of unprecedented versatility in flat, multilevel diffractive lenses (MDLs).
Our research group has demonstrated binary multi-level diffraction lenses in three high performance categories: super-achromatic lenses in three wavelength regions (8-12um 0.45-1 um, 1.5-150 um), high NA of 0.9 of at 0.85um, and extreme depth of focus (5mm to 1200mm).
We believe that our inverse-designed flat MDLs, which can be manufactured using low-cost imprinting techniques, could prove widely applicable—especially where weight and restricted form factor are important considerations, as in aerospace and airborne imaging as well as augmented and virtual reality displays.
No fee for this on-line webinar.
Log-in credentials will be e-mailed June 9, 2021.
Recent OSSC Meetings
OSSC Online Webinar, Thursday May 20, 2021, 6:30pm
“Redefining precision laser optics with substrate-transferred crystalline coatings”
Dr. Garrett Cole, Technology Manager,
Thorlabs Crystalline Solutions
Substrate-transferred crystalline coatings are a groundbreaking new concept in optical interference coatings, leveraging a combination of semiconductor materials and microfabrication techniques with super-polished bulk optics technologies.
These coatings are generated via a unique manufacturing process entailing separate crystal growth, microfabrication, and direct bonding that yields single-crystal coatings on arbitrary—including curved—optical surfaces. These “semiconductor supermirrors” were first demonstrated in 2013 with the key advantage being the ability to achieve ultralow levels of both optical and elastic losses.
With continuous refinement in production and metrology, we have reduced the scatter + absorption losses to < 5 parts per million (ppm) for near-IR wavelengths spanning 1064 to 1560 nm, enabling a cavity finesse exceeding 300,000 (mirror reflectance > 99.999%). In this spectral range, crystalline coatings are now fully competitive with ion beam sputtered films, while simultaneously yielding a significant reduction in Brownian thermal noise, a fundamental limitation in the stability of laser-based precision measurement systems including gravitational wave detectors and cavity-stabilized lasers for optical atomic clocks.
Additional advantages of these novel monocrystalline coatings include record-low-levels of mid-infrared optical losses, as well as an exceptionally high thermal conductivity for an ultralow-loss optical interference stack. Looking ahead, we see a bright future for crystalline coatings in applications requiring the ultimate levels of optomechanical and thermal performance.