Fig. 1. Post-spectral technology

Fig. 2. Grating diffraction principle. (a) Holographic concave grating; (b) Rowland grating

Fig. 3. 3D principle schematic. (a) Spectroscopic structure; (b) overall light path

Fig. 4. Spot diagrams. (a) Spot diagram at 340 nm; (b) spot diagram at 405 nm; (c) spot diagram at 505 nm; (d) spot diagram at 600 nm; (e) spot diagram at 660 nm; (f) spot diagram at 790 nm

Fig. 5. RMS of Y' versus wavelength

Fig. 6. Prototype structure. (a) Schematic of spectrophotometer structure; (b) photograph

Fig. 7. Actual spectrogram

Fig. 8. Schematic of current-voltage amplification principle

Fig. 9. Repeatability test. (a) Repeatability at 350 nm; (b) repeatability at 475 nm; (c) repeatability at 800 nm

Fig. 10. Fitted lines. (a) Fitted line at 340 nm of #1; (b) fitted line at 405 nm of #1; (c) fitted line at 340 nm of #2; (d) fitted line at 405 nm of #2

Fig. 11. Relationship between absolute value of relative bias and relative concentration