HILA – ultrastable optical cryostat with new auto-leveling feature
When planning a sensitive, optical low-temperature experiment and searching for the right optical cryostat, most people think they need a system with low vibration amplitude. For the most applications this is correct but by far not for all of them. For many setups like scanning probe microscopes (SPM) or tunable cavities and as long as a fiber-based optic is used, only the accelerations in the sample space play a role. A low acceleration does not necessarily correlate with a low amplitude.
The Cryostation HILA is an optical cryostat with high-performance vibration isolation. HILA stands for “High Inertia Low Acceleration”. The sample chamber is almost completely isolated from the movement of the cold head by a combination of compensators and elastomeric isolators with “negative stiffness”. The technique is similar to the vibration isolation at the LIGO interferometer.
The floating sample platform isolates kinetic energy for an ultra-stable mechanical environment with almost no acceleration and boasts an extremely low natural frequency. In the latest HILA generation, the sample platform outline is traced with feedback positioners to also keep the amplitude of the floating platform low. When an objective is installed inside the sample chamber and the backside of the objective is overfilled by the laser, the spot does not move relative to the sample, even when the platform oscillates slowly. Auto leveling allows the use of free space optics with the HILA. So far, it has been recommended to use fiber-based optics for this kind of setting.
- Temperature range: 4.5 K – 350 K
- Acceleration: 0.024 m/s2
- Natural frequency: < 0.6 Hz