Lexel Model 503 Etalon Assembly

LEXEL MODEL 503 ETALON

The Lexel Model 503 Temperature-Controlled Etalon Assembly, when installed in a Lexel ion laser, provides extremely stable single frequency operation for applications requiring long coherence length and very narrow linewidth. For holography and interferometry, it can provide coherence lengths of over 100 meters. For Brillouin scattering and high resolution spectroscopy, it provides a linewidth of approximately 10^-4 cm^-1 (3 MHz).

Solid fused silica etalon
Etalon heater Provides precise temperature control of frequency and mode tuning.
Etalon tuning plate Holds etalon assembly in precise mechanical alignment.
Etalon tuning screws Adjusts etalon tilt angle for maximum efficiency (factory set).
Resonator end plate End support for Invar resonator.
Etalon and mirror mount springs Provides tension for the kinematic suspension system.
Mirror tuning plate Holds prism wavelength selector in precise mechanical alignment.
Tuning screws Allow tuning and selection of the various ion laser wavelengths.
Prism wavelength selector
Etalon retainer Secures etalon in position.
Dust cover Provides dust-free seals between the laser Brewster window and the etalon retainer.
Solid Invar resonator rods Low thermal expansion structure provides a rigid, low-vibration optical cavity.
Flexible seal Provides movable seals between the etalon tuning plate and the mirror tuning plate.
O-ring Completely seals the etalon into the optical cavity.
Thermistor Provides temperature feedback to the temperature control electronics.
Printed circuit card electronics Contains electronics for the advanced etalon control circuit.

MODEL 503 ETALON ASSEMBLY SPECIFICATIONS
Etalon material	Fused silica (Suprasil 1)
Etalon dimensions	15 mm dia. x 11 mm long
Surface parallelism	Better than 0.5 arc seconds
Free spectral range (c/2nt)	9.4 GHz
Etalon control	Temperature tuned and stabilized
Etalon temperature regulation	Better than 0.01°C
Etalon frequency stability	Better than ± 20 MHz regardless of ambient temperature changes -- virtually no mode hopping
Single frequency stability	Δv < ± 5 MHz for T < 1 sec
Typical single frequency linewidth	≈ 3 MHz (10^-4 cm^-1)
Typical coherence length	≈ 100 meters
Conversion efficiency (SLM Power/MLM Power)	50% to 75% on major lines
Longitudinal mode spacing (c/2L) Model 85 series Model 95 series	188 MHz (0.8 meter cavity) 150 MHz (1.0 meter cavity)
Resonator design	Solid Invar^® rod structure
Temperature tuning range	≈ 10 GHz
Temperature tuning factor	≈ 3 MHz/degree rotation of the Etalon Temperature Tuning control (≈ ¼ turn/mode)
NOTE: The frequency, stability, linewidth and coherence lengths listed above are based on the best short-term values resolved in Lexel's laboratory. Different environmental conditions may result in different values. The long-term coherence length may be calculated from S ≈ (c/Δv) where c is the velocity of light and Δv is the maximum frequency excursion during the time involved. For example, if Δv is ± 15 MHz, the coherence length will be S ≈ ( (3x108 m/sec) / (30 x 106 Hz) ) ≈ 10 meters. It is recommended that Lexel lasers operated with the Model 503 Etalon Assembly also be equipped with the Model 500 Temperature Compensated Prism Wavelength Selector. The Model 503 Etalon Assembly is sold only for use in Lexel ion lasers.
Specifications as of 5/2003. Subject to change without notice.

Click here for detailed information about single-frequency operation with the Lexel Model 503 Etalon Assembly