Table 6.
Summary of the performances of different optical ultrasound detection techniques. Reproduced from [41,42].
| Method | Configuration | Readout Element Diameter/Dimension (μm) | Detection Geometry | BW (MHz) | NEP (Pa) | Ref. | |
|---|---|---|---|---|---|---|---|
| Interferometric | MI | ** | Point; disk | 5; 20 | 35; 275 | [179] | |
| MZI (free space) | 90 | Bar | 17.5 | 100 (x mm) | [176] | ||
| MZI (fiber optic) | 125/8 | Bar | 50 | 92 × 103 (x mm) | [180] | ||
| Doppler | -/12 | Point | 10 | - | [181] | ||
| RI | FP (free space) | ** | Bar | 25 | 20 | [182] | |
| FP (fiber optic) | 125/8 | Bar | 50 | 1 | [180] | ||
| MRR (integrated) | 60/0.8 × 0.8 | Ring | 140 | 6.8 | [183] | ||
| FBG (fiber optic) | 125/8 × 100 | Bar | 20 | 450 | [184] | ||
| FBG (integrated) | 500/1.5 × 1.5 | Bar | 60 | 6.5 × 103 | [185] | ||
| Refractometric | Intensity-sensitive | 15 × 10−3 | Prism | 100 | 100 * | [186] | |
| Deflectometry | 90 | Needle beam | 17 | 2.76 * | [172] | ||
| Phase-sensitive | 10−2 | Schlieren | 110 | 486 * | [174] | ||
* Unit: mPA·Hz−1/2, ** Diffraction limited, BW: bandwidth; NEP: noise equivalent pressure, MI: Michelson interferometry; MZI: Mach–Zehnder interferometry; DI: doppler- interferometry; RI: resonator- interferometry.