Increasing of Spectral Resolution of Multislit Imaging Spectrometer with Diffractive Grating

Registration of non-stationary processes, namely snapshot hyperspectral imaging that allows to capture data cube I(x,y,λ) in one measurement act, is of interest for imaging spectroscopy.

The purpose of the work is increasing of spectral resolution of imaging spectrometers with spatial filtering of object image using multislit mask, where a diffractive grating is used as disperser (providing almost constant dispersion in working spectral range), and the data cube is projected on a detector as a set of local spectra from object fragments.

An image is formed on detector by a two-objective telecentric system composed from two lenses focused on infinity so that their front focuses are matched. A diaphragm in the match point allows passing only for beams of needed diffraction order, so along with a bandpass filter near the system entrance they solve a typical problem of diffractive systems – elimination of beams of all orders but a needed one. The approach is implemented in two proposed designs of spectrometers: in the first a telecentric system is based on two multi-lens imaging objectives, in the second – is based on two reflective off-axis parabolic objectives.

In this paper we proposed variants for optical design optimization: normalization of beam incidence on a mask and field curvature compensation; they allow to increase system resolution and to extend application area of multislit dispersive spectrometers; also a design being a synthesis of these two approaches is analyzed. According to simulation results, width on half-maximum in dispersion direction Δl ≤ 10 µm, only for limited field points set Δl ≤ 15 µm, that stands for spectral resolutio

snapshot hyperspectroscopy, multislit dispersive spectrometer, parabolic mirror lens, telecentric system

1. Xie Y., Sha Z., Yu M. Remote sensing imagery in vegetation mapping: a review. Journal of Plant Ecology, 2008, vol. 1, no. 1, pp. 9–23. DOI: https://doi.org/10.1093/jpe/rtm005

2. Lu G., Fei B. Medical hyperspectral imaging: a review. Journal of Biomedical Optics, 2014, vol. 19, no. 1, pp. 010901-1–010901-23. DOI: https://doi.org/10.1117/1.JBO.19.1.010901

3. Thompson D.R., Leifer I., Bovensmann H., Eastwood M., Fladeland M., Frankenberg C., Gerilowski K., Green R.O., Kratwurst S., Krings T., Luna B., Thorpe A.K. Real-time remote detection and measurement for airborne imaging spectroscopy: a case study with methane. Atmospheric Measurement Techniques, 2015, vol. 8, no. 10, pp. 4383–4397. DOI: https://doi.org/10.5194/amt-8-4383-2015

4. Kuula J., Pölönen I., Puupponen H., Selander T., Reinikainen T., Kalenius T., Saari H. Using VIS/NIR and IR spectral cameras for detecting and separating crime scene details. Proceedings SPIE, 2012, vol. 8359, pp. 83590P-1– 83590P-11. DOI: https://doi.org/10.1117/12.918555

5. Qin J., Chao K., Kim M.S., Lu R., Burks T.F. Hyperspectral and multispectral imaging for evaluating food safety and quality. Journal of Food Engineering, 2013, vol. 118, no. 2, pp. 157–171. DOI: https://doi.org/10.1016/j.jfoodeng.2013.04.001

6. Gao L., Smith R.T. Optical hyperspectral imaging in microscopy and spectroscopy – a review of data acquisition. Journal of Biophotonics, 2015, vol. 8, no. 6, pp. 441–456. DOI: https://doi.org/10.1002/jbio.201400051

7. Lefebvre J. Real Time Hyperspectroscopy for Dynamical Study of Carbon Nanotubes. ACS Nano, 2016, vol. 10, no. 10, pp. 9602–9607. DOI: https://doi.org/10.1021/acsnano.6b05077

8. Mouroulis P., Green R.O., Chrien T.G. Design of pushbroom imaging spectrometers for optimum recovery of spectroscopic and spatial information. Applied Optics, 2000, vol. 39, no. 13, pp. 2210–2220. DOI: https://doi.org/10.1364/AO.39.002210

9. Tran C.D. Principles, Instrumentation, and Applications of Infrared Multispectral Imaging, An Overview. Analytical Letters, 2005, vol. 38, no. 5, pp. 735– 752. DOI: https://doi.org/10.1081/AL-200047754

10. Hagen N., Kudenov M.W. Review of snapshot spectral imaging technologies. Optical Engineering, 2013, vol. 52, no. 9, pp. 090901-1–090901-23. DOI: https://doi.org/10.1117/1.OE.52.9.090901

11. Sugai H., Hattori T., Kawai A., Ozaki S., Hayashi T., Ishigaki T., Ishii M., Ohtani H., Shimono A., Okita Y., Matsubayashi K., Kosugi G., Sasaki M., Takeyama N. The Kyoto tridimensional spectrograph II on Subaru and the University of Hawaii 88-in telescopes. Publications of the Astronomical Society of the Pacific, 2010, vol. 122, no. 887, pp. 103–118. DOI: https://dx.doi.org/10.1086/650397

12. Bodkin A., Sheinis A., Norton A., Daly J., Beaven S., Weinheimer J. Snapshot hyperspectral imaging – the hyperpixel array camera. Proceedings SPIE, 2009, vol. 7334, pp. 73340H-1–73340H-11. DOI: https://doi.org/10.1117/12.818929

13. Volin C.E., Gleeson T.M., Descour M.R., Dereniak E.L. Portable computed-tomography imaging spectrometer. Proceedings SPIE, 1996, vol. 2819, pp. 224–230. DOI: https://doi.org/10.1117/12.258068

14. Kudenov M.W., Dereniak E.L. Compact real-time birefringent imaging spectrometer. Optics Express, 2012, vol. 20, no. 16, pp. 17973–17986. DOI: https://doi.org/10.1364/OE.20.017973

15. Gulis I.M., Kupreyeu A.G., Demidov I.D., Voropay E.S. [Multislit diffraction grating spectrometer for imaging spectroscopy]. J. Belarus. State Univ. Phys., 2017, no. 3, pp. 4–11 (in Russian).

16. Gulis I.M., Kupreyeu A.G., Demidov I.D. [Multislit diffraction grating spectrometer with mirror lens for imaging spectroscopy]. J. Belarus. State Univ. Phys., 2018, no. 2, pp. 4–10 (in Russian).

17. Schroeder D.J. Astronomical optics, 2nd edition. San Diego, Academic Press, 1999, 478 p.