attoCFM IV
free-beam/fiber-based confocal microscope for transmission
combination of attoCFM I and attoCFM III
transmission via 1 free-beam & 1 fiber-based channel
unmatched long-term drift stability
measure single photon signals over extended periods
independent position both objectives in xyz
pump-probe @ large lateral separation (up to 3 mm)
Transmission experiments in confocal microscopy sometimes also require filtering and shaping of the optical beam, and hence free-beam access instead of purely fiber-based can have quite some advantages in terms of flexibility.
This instrument literally consists of a ‚conventional‘ attoCFM I, which has a free-beam based channel with any of our apochromatic objectives above the sample, and a fiber-based channel from below just like in the attoCFM III. So, despite fitting into any of our toploading cryostats, which usually features only 1 top and no side or bottom windows, this setup allows for at least either the excitation or the detection to be free-beam.
This provides the user with all the flexibility of the external optics head just like in case of the attoCFM I for one channel (plus potential reflection measurements).
At the same time, there are 3 degrees of freedom for the sample (xy translation under the fixed LT-APO objective as well as focussing), and another 3 degrees of freedom in xyz to position the fiber-based objective underneath the sample. All positioners are usually equipped with a /RES encoder for closed loop control, and there is an additional scanner for the sample in xy direction. For more info please refer to the fundamentals section.
Specifications
| General Specifications | |
|---|---|
| type of instrument | confocal microscope for transmission experiments with one free-beam and one fiber based channel |
| sensor head specifics | one channel with unique LT compatible achromatic objectives with high numerical aperture, optimized for different wavelength ranges, and one channel with fiber-coupled LT compatible aspheric objective |
| Confocal Unit | |
| configuration | compact and modular design, two or more optical channels; standard configuration: one excitation and one detection channel |
| key benefits | quick and reliable alignment of each channel, steering mirror for combined beams long-term stability |
| quick-exchange of optical components | beamsplitters, filter mounts for up to 4 filters/polarizers, (1" diameter); optional piezoelectric rotator with filter mount |
| pinhole configuration | two pinholes (fiber apertures), different illumination and collection wavelength possible |
| pinhole size | dependent on fibers, typically 3 .. 9 µm mode field diameter |
| compatible LT-objective | LT-APO/VIS, LT-APO/VISIR, LT-APO/NIR (see accessory section for more information) |
| inspection unit | sample imaging with large field of view: ~54 µm (attoDRY) |
| Illumination | |
| illumination port specification | FC/ APC-connector for single mode fibers or free-beam configuration |
| Detection | |
| detection mode | e.g. transmission, reflection, luminescence, fluorescence, Raman (optional) |
| detection wavelength range | free-beam channel 400 .. 1000 nm, default 650 nm (others on request), fiber channel limited to wavelength range of single mode fiber, default 650 nm (others on request) |
| detection port specification | free-beam configuration or FC/ APC-connector for single mode fibers |
| Sample Positioning | |
| total travel range | sample 3 x 3 x 2.5 mm³ (closed loop), fiber-based objective 5 x 5 x 4.8 mm³ (closed loop) |
| step size | 0.05..3 µm @ 300 K, 10..500 nm @ 4 K |
| fine scan range | sample 30 x 30 µm² @ 300 K, 12 x 12 µm² @ 4 K (open loop) |
| sample holder | Ti plate with aperture of 8 mm in diameter with integrated heater and calibrated temperature sensor |
| Suitable Operating Conditions | |
| temperature range | 1.5 K..300 K (dependent on cryostat); mK compatible setup available on request |
| magnetic field range | 0..14 T (dependent on magnet)(16 T compatible version available on request) |
| operating pressure | designed for He exchange gas |
| Suitable Cooling Systems | |
| titanium housing diameter | 48 mm |
| bore size requirement | designed for a 2" (50.8 mm) cryostat/magnet bore |
| compatible cryostats | attoDRY1000/1100/2100 |
| Compatibility with Electronics | |
| scan controller and software | ASC500 basic (optional; for detailed specifications please see attoCONTROL section) |
| laser | LDM600 laser/detector module (for detailed specifications please see attoCONTROL section) |
