Table 1.

Technical specifications of the slit-based and coded aperture instruments. Notice that the coded aperture instrument provides a larger collection area than the slit-based instrument ($15.4\times {10}^6$ versus $52.0\mu {\mathrm{m}}^2$) while maintaining a similar spectral resolution and collection numerical aperture (NA). This is because of the sharp difference in étendue, which is nearly 6 orders of magnitude greater for the coded aperture instrument.

	Slit based	Coded aperture
Illumination wavelength (nm)	785	785
Illumination power (mW)	10	85
Illumination area ($\mu {\mathrm{m}}^2$)	80 (circular)	$8\times {10}^6$ (elliptical)
Working distance (mm)	10.6	1.5
Spectral resolution (${\mathrm{cm}}^{-1}$)	10	7
Collection NA	0.5	0.45
Collection area ($\mu {\mathrm{m}}^2$)	52.0 ($2\times 26$)	$15.4\times {10}^6$ ($4400\times 3500$)
Étendue ($\mu {\mathrm{m}}^2\mathrm{sr}$)	43.8	$10.4\times {10}^6$