Optical Microphones
For airborne acoustic sensing and process monitoring, the Optical Microphone can be used as a standalone sensor or as part of a complete measurement system.
For dry ultrasonic NDT applications, the Optical Microphone is used together with a XARION excitation laser.
| Eta100 Ultra | Eta250 Ultra | Eta450 Ultra | Eta600 Ultra | |
|---|---|---|---|---|
| Frequency range | 10 Hz – 1 MHz | 10 Hz – 1 MHz | 50 kHz – 2 MHz | 50 kHz – 4 MHz |
| Self-noise | 1.5 mPa (BW: 1 Hz, measured @ 1 kHz) | 50 µPa (BW: 1 Hz, measured @ 1 kHz) | 5 µPa (BW: 1 Hz, measured @ 500 kHz) | 3.5 µPa (BW: 1 Hz, measured @ 500 kHz) |
| Self-noise, full bandwidth | 1.5 Pa | 50 mPa | 10 mPa | 10 mPa |
| Dynamic range | 100 dB | 100 dB | 100 dB | 95 dB |
| Max. sound pressure level for THD | 176 dB rel. 20 µPa | 146 dB rel. 20 µPa | 126 dB rel. 20 µPa | 120 dB rel. 20 µPa |
| Analog BNC output | ±15 V (high-Z), ±7.5 V (50 Ω) | ±15 V (high-Z), ±7.5 V (50 Ω) | ±15 V (high-Z), ±7.5 V (50 Ω) | ±15 V (high-Z), ±7.5 V (50 Ω) |
| Typical application area | Sound field characterization | Process monitoring, Sound field characterization | Non-destructive testing, process monitoring, sound field characterization | Non-destructive testing |
The Eta450 and Eta600 are also available as multi-channel array receivers, offering 8, or 16 channels. Array configurations enable scanning speeds of up to 1 m/s – covering 50 m²/h (540 ft²/h) – making them ideal for efficient large-area inspection.