attoCFM I

free-beam confocal microscope

low temperature, high-NA apochromatic objectives

broadband collection with low focal displacement

free-beam Faraday and Voigt geometry available

in-/out-of-plane configuration with single solenoid

unmatched long-term drift stability

measure single photon signals over extended periods


The attoCFM I has been developed to offer a maximum amount of flexibility for a convenient adaption to a large number of different quantum optics applications. This is realized by an external optics head, positioned outside the cryostat. Furthermore, the free-beam optical design allows for completely independent adjustment of the excitation and collection port. Therefore, applications such as Raman spectroscopy become accessible by appropriately filtering of the excitation and detection signals.

The easy handling opens up new possibilities in quantitative surface characterization in the sub-micron range. The attoCFM I is available with an optional interferometric encoder for closed loop operation. All parts are non-magnetic, and it is compatible with all attoCRYO setups with a 2” sample space and exchange gas cooling – whether it is a dry or a liquid setup. For more info please refer to the fundamentals section.

Cryogenic Tablet


Suitable Operating Conditions
temperature range1.5 K..300 K (dependent on cryostat); mK compatible setup available on request
magnetic field range0..15 T+ (dependent on magnet)
operating pressuredesigned for He exchange gas (vacuum compatible version down to 1E-6 mbar on request)
General Specifications
type of instrumenttransport measurement module for angledependent magneto-resistance measurements
sensor head specificsunique low temperature compatible achromatic objectives with high numerical aperture, optimized for different wavelength ranges
Suitable Cooling Systems
titanium housing diameter48 mm
bore size requirementdesigned for a 2" (50.8 mm) cryostat/magnet bore
compatible cryostatsattoDRY1000/1100/2100, attoLIQUID1000/2000 (attoLIQUID3000/5000 on request)
Confocal Unit
configurationcompact and modular design, two or more optical channels; standard configuration: one excitation and one detection channel
key benefitsquick and reliable alignment of each channel, steering mirror for combined beams long-term stability
quick-exchange of optical componentsbeamsplitters, filter mounts for up to 4 filters/polarizers, (1" diameter); optional piezoelectric rotator with filter mount
pinhole configurationtwo pinholes (fiber apertures), different illumination and collection wavelength possible
pinhole sizedependent on fibers, typically 3 .. 9 µm mode field diameter
compatible LT-objectiveLT-APO/VIS, LT-APO/VISIR, LT-APO/NIR (see accessory section for more information)
inspection unitsample imaging with large field of view: ~54 µm (attoDRY), ~40 µm (attoLIQUID)
Compatibility with Electronics
scan controller and softwareASC500 basic (optional; for detailed specifications please see attoCONTROL section)
laserLDM600 laser/detector module (for detailed specifications please see attoCONTROL section)
Options and Upgrades
closed loop scanning & global sample coordinatesinterferometric encoders for scan linearization and closed loop sample navigation
ultra-large scan range upgrade80 x 80 µm² @ 300 K, 125 x 125 µm² @ 4 K
in-situ inspection opticsincl. with CFM I external optics head
closed loop upgrade for coarse positionersresistive encoder, range 5 mm, sensor resolution approx. 200 nm, repeatability 1-2 µm
sample holder upgradeASH/QE/4CX quick-exchange sample holder (8 electrical contacts, integrated heater & T-sensor)
Voigt geometry upgradeoptional scanner for Voigt & Faraday geometry
excitation wavelength range400 .. 1000 nm, default 650 nm (others on request)
illumination port specificationFC/ APC-connector for single mode fibers or free-beam configuration
detection modee.g. reflection, luminescence, fluorescence, Raman (optional)
detection wavelength rangedetector upon user`s choice, typically Si detector (coupling of the light to other detectors)
detection port specificationFC/ APC-connector for single mode fibers or free-beam configuration
transmission optionlow temperature compatible detector below the sample for transmission measurements (intensity)
Sample Positioning
total travel range5 x 5 x 5 mm³ (open loop)
step size0.05..3 µm @ 300 K, 10..500 nm @ 4 K
fine scan range50 x 50 µm² @ 300 K, 30 x 30 µm² @ 4 K (optional, open loop)
closed loop scan resolution (steady state, 100 ms sample time)1 nm rms typ.
sample holderASH/QE/0 quick exchange sample holder and integrated heater with calibrated temperature sensor
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Customer Feedback

Dr. J. Szczytko

Institute of Experimental Physics, University of Warsaw, Poland

One of the real advantages of the attocube CFM I system is its flexibility – one can use the attocube CFM I optics setup for many optical applications – e.g. reflectivity, up-conversion and of course luminescence. You can control polarization of the light independently at detection and excitation ports. You can easily connect a spectrometer and record images and spectra at the same time. Together with the new LT-objectives from attocube, this works great!

Prof. M. Daldin

UFSCar, Universidade Federal de São Carlos, São Carlos, Brazil

Thanks to the versatility of the attoDRY1000 used with the attoCFMI, the system has been serving our research group in different kinds of optical and electronic transport measurements. It's incredible stability on a cryo-free enviroment is the key for succesfully running measurements over long periods of time. We are also very glad with the first class technical support provided by attocube.