Iodine-Stabilised HeNe Reference Lasers
- Available at 633 nm (red) or 543 nm (green)
- Fully compliant with the International Committee of Weights and Measures CIPM 1997/2001 'Mise en pratique' recommendations for the realisation of the metre
- Frequency uncertainties (1 sigma):
- 2 × 10-10 at 633 nm
- 2.5 × 10-10 at 543 nm
- Primary laser reference standards for realisation of the metre and precision length metrology
- Calibration references for stabilised lasers
- Optical frequency references for high resolution spectroscopy
Iodine stabilised He-Ne lasers are used in many national standards laboratories and measurement institutes for the practical implementation of the SI unit of length, the metre. Such systems offer an accurate and effective means of delivering traceability for length and dimensional measurement within the precision engineering and manufacturing industries. NPL has long standing research and development experience of iodine stabilised lasers, going back over 30 years, and operates a number of systems in house as the UK national standard of length.
The robust iodine-stabilised 633 nm reference system is a new product that has a range of user-friendly properties:
- Laser locks to an iodine component automatically within about 20 minutes after turn-on. Automatic lock monitoring without the need of a PC and logic output indicates whether laser is in lock
- Output power > 0.3 mW
- Unmodulated frequency output
- Frequency lock not sensitive to acoustic or ground-borne noise and can lock in a much noisier environment
NPL has provided 633 nm red and 543 nm green iodine stabilised HeNe reference lasers to national measurement institutes and precision metrology companies worldwide. NPL can install and commission the lasers, and provide full training for system operators. Software is also available for automatic calibration and certification of test lasers.
Laser beat frequency monitoring systems for calibration of industrial stabilised lasers are also available.
| System Wavelength | 633 nm (provisional) | 543 nm |
| Frequency stability (10 s averaging time) |
Typically 2 × 10-11 | <5 × 10-11 |
| Frequency uncertainty (1s) | 2 × 10-10 | 2.5 × 10-10 |
| Active stabilisation | Iodine saturation using FM signal recovery | Iodine saturation using FM signal recovery |
| Accessible 127I2 hyperfine components | b21 of the 6-3 P(33) transition | b11-b15 of the 28-0 R(106) transition |
| Iodine absorption cell | NPL high purity | NPL high purity |
| Iodine cell sidearm temperature | Room temperature | 0 ± 2 °C Peltier cooled |
| Single frequency tuning range | Not applicable (tunes to only one iodine component) | 500 MHz |
| Output power | 300 µW | 30 µW |
| Output polarisation | Linear, horizontal | Linear, horizontal |
| Plasma tube | Internal mirror | Internal mirror |
| Continuous frequency lock over 24 hours for ambient temperature 20 ± 5 °C | YES | YES |
| Automatic lock-in | YES | YES |
| Manual tune/lock-in | NO | YES |
| Stabilisation electronics | Standard 19” rack | Standard 19” rack |
| AC line voltages | 110-120 V, 220-240 V | 110-120 V, 220-240 V |
Contact
Customer Service tel: +44 20 8943 6796
E-mail: laser_enquiries@npl.co.uk
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