Design and implementation of a sub-nm resolution microspectrometer based on a Linear-Variable Optical Filter

Abstract

Abstract:In this paper the concept of a microspectrometer based on a Linear Variable Optical Filter (LVOF) for operation in the visible spectrum is presented and used in two different designs: the first is for the narrow spectral band between 610 nm and 680 nm, whereas the other is for the wider spectral band between 570 nm and 740 nm. Design considerations, fabrication and measurement results of the LVOF are presented. An iterative signal processing algorithm based on an initial calibration has been implemented to enhance the spectral resolution. Experimental validation is based on the spectrum of a Neon lamp. The results of measurements have been used to analyze the operating limits of the concept and to explain the sources of error in the algorithm. It is shown that the main benefits of a LVOF-based microspectrometer are in case of implementation in a narrowband application. The realized LVOF microspectrometers show a spectral resolution of 2.2 nm in the wideband design and 0.7 nm in the narrowband design. 51-54 (1994). 13. K. Burns, K. B. Adams, and J. Longwell, "Interference measurements in the spectra of neon and natural mercury," J. Opt. Soc. Am. 40(6), 339-344 (1950 ©2011 Optical Society of America

Medical apps in need of optical microspectrometers

“…A highly successful concept for narrowband spectroscopy is the Linearly variable Optical Filter (LVOF) (Emadi et al 2012). As the tapered FP filter is fabricated directly on top of a detector array using low-temperature processing on cleanroom-compatible materials, CMOS-compatibility is possible for on-chip functional integration.…”

Linear variable optical filter-based ultraviolet microspectrometer

“…The signal processing required is similar to that described in [24] and presented for a visible LVOF microspectrometer in [10]. The technique is summarized here.…”

“…The result demonstrates that the LMS signal processing technique is suitable for measurements in the case of a continuous spectrum, as is the case of a mercury lamp. The suitability of the LMS algorithm for a spectrum with discrete features was shown in [10] for an LVOF microspectrometer operating in the visible spectrum by measuring the spectrum of a neon lamp. …”

“…Such an LVOF-based microspectrometer was reported for the visible spectral range by combining an LVOF with a CMOS camera [10]. In this article, we present the optical design, implementation, and signal processing required for implementing an LVOF microspectrometer in the UV spectral range.…”

Compact gas cell integrated with a linear variable optical filter

“…2(a). Several research groups have reported miniaturized light sources [18][19][20], optical filters [17,[21][22][23][24][25][26][27][28], and detectors [29,30]. However, the sample cell which is used for storing the sample gas occupies a large part of the microspectrometer.…”