Q&A

Hubert Kostal is the vice president of marketing and sales for NanoOpto Corporation (Somerset, NJ), a company that is applying proprietary nano-optics and nano-manufacturing technology to design and make components for optical systems and networks.

The full interview – “Nano-Optics for Camera Applications” – is available on page IIa of the July 2005 issue of Photonics Tech Briefs (PTB). Selectively bound into NASA Tech Briefs, PTB focuses on innovative new technologies and products available for commercial application in the fields of optics, lasers, electro-optics, test & measurement, fiber optics, and imaging. Visit PTB online at www.ptbmagazine.com.

Nanotech Briefs: How are nano-optic filters used in commercial applications?

Hubert Kostal: Nano-optic filters can be used as drop-in replacements for traditional optical components, such as band pass, polarizing, wavelength selective, and optical low-pass filters, in applications ranging from cell phone camera modules and digital cameras to industrial and satellite imaging systems.

IR cut-off filters (IRCF – a type of band pass filter), for instance, are often capable of detecting a broader range of wavelengths than is desired for a particular application. For standard photography applications, this requires blocking IR wavelengths and passing visible wavelengths. For security applications, the reverse may be required – passing IR and blocking visible wavelengths.

Nano-optic functions like IRCF can be deposited on the cover plate of the CCD sensor in the camera module. This eliminates a physically separate filter component, simplifying assembly and alignment. This approach takes advantage of the optical uniformity of nano-optic devices.

The fabrication process results in a defect free, highly uniform surface coating that can be index matched to adjoining layers, so the IRCF function can be placed close to or in the focal plane. The functional layer of the IRCF is very thin, only a few microns in thickness. The substrate on which it resides is non-functional and acts only as a carrier – changing the thickness of the carrier allows adjustment of the device thickness to application requirements.

The dielectric materials used in the design are robust relative to environmental conditions. In particular, damp heat does not affect the optical performance of the IRCF. Nano-optic IRCFs also offer excellent optical performance, especially high transmission across the visible spectrum (including in the red portion of the spectrum), with extremely sharp cut-offs at the UV and IR ends of the spectrum.

For more information, contact Hubert Kostal at hkostal@NanoOpto.com or visit www.NanoOpto.com.

A nano-optic IR cut-off filter is a nano-optic band pass filter designed specifically for camera module applications. It exhibits excellent optical performance (industry standard requirements are indicated on the chart) and, because of material selection, excellent robustness and reliability.