A high-resolution spectrometer based on a compact planar two dimensional photonic crystal cavity array

Abstract

We demonstrate a compact spectrometer based on an array of high-quality-factor photonic crystal nanocavities, coupled via a planar two-dimensional waveguide. This architecture enables spectral analysis of incident light with resolution as high as the bandwidth of the cavity mode–0.3 nm at 840 nm for our device. The design is easily extended to the visible and deep-infrared spectral ranges. The two-dimensional cavity array can be mated to commercial two-dimensional optical detector arrays, creating a compact and high-resolution spectrometer suitable for a range of applications including materials and chemical analysis.

High performance graphene oxide-based humidity sensor integrated on a photonic crystal cavity

“…The cavity excitation and reflection are coupled vertically using an 50× objective lens with a numerical aperture of 0.42. With the orthogonally polarized input and output, the reflection of the cavity mode could be distinguished with a high signal to noise ratio [16]. The employed light source is a narrowband tunable telecom laser, and the cavity reflection is detected by a photodiode.…”

On-chip spectroscopy with thermally tuned high-Q photonic crystal cavities

“…The light scattered by each resonator, either vertically, as in Gan et al, 12 or into output waveguides, as in Xia et al, 10 is monitored and used to reconstruct the input spectrum. The resolution of such a spectrometer is given by the spectral width of the frequency response of the individual elements, which is typically of the order of 10 GHz.…”

“…7 However, these devices tend to be rather large, with a resolution in wavenumbers (cm −1 ) typically given by 1/L, where L is the characteristic size of the dispersive region in cm. Spectrometers can also be constructed by cascading optical elements with narrow-band spectral responses, such as Fabry-Pérot filters, 8 grating couplers, 9 microdonut resonators, 10 photonic crystal cavities [11][12][13] etc. The operating principle of such a spectrometer is shown schematically in Fig.…”

High-resolution optical spectroscopy using multimode interference in a compact tapered fibre

“…In recent years, there has been a strong effort to develop novel spectrometers that are compact and have high resolving powers and operational bandwidths 5,[12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] . In addition to miniature grating spectrometers 12 , resonant structures such as nanocavities [13][14][15][16][17][18] have also been employed to separate spectral components into unique detectors.…”

“…In addition to miniature grating spectrometers 12 , resonant structures such as nanocavities [13][14][15][16][17][18] have also been employed to separate spectral components into unique detectors. This research has produced millimetre-scale spectrometers with high resolving powers of R410 4 , but with limited fractional bandwidth,…”