Advanced Measurement Facilities

University: University of Melbourne

Venue City: Melbourne

Cryogenic Quantum Microscope Facility

The University of Melbourne cryogenic quantum microscope facility, installed in 2018, combines a closed-cycle pulsed-tube cryostat from Attocube Systems with a wide-field optical microscope equipped with a 532 nm laser and a sCMOS camera. The cryostat also comprises a superconducting 3D vector magnet (1-1-1 Tesla). This facility enables quantum sensing/microscopy based on diamond NV centres from room temperature down to 4 K. It will be used to perform spin spectroscopy and image magnetism or charge transport in various low-dimensional systems, for instance to characterize silicon quantum processors or develop single molecule MRI.

Advanced Spectroscopy

The Melbourne Node is home to two commercial micro-Raman Spectrometers for conducting Ultra-Violet, Visible and Near Infra-Red Raman and Luminescence studies. The Renishaw RM 1000 is located within the CQC2T Cleanroom. This system is a single grating, extended wavelength Raman/luminescence spectrometer (244–1000nm) with Coherent I90 FRED, Kimmon HeCd and Stellar Pro Modulaser excitation sources. The Renishaw Invia Reflex has recently been moved from Bio21 into a new spectroscopy laboratory next to the Cleanroom. This system is integrated with a Philips XL30SEM allowing in-situ optical measurements. This system is configured with both visible (532nm) and near infrared (1064nm) excitation sources and visible and NIR (out to 1.7 µm) detection capabilities. A SULA Deep Level Transient Spectroscopy (DLTS) system and Hall system is also housed within the Melbourne node to electrically characterise devices.

Dilution Refrigerator

The low-temperature laboratory has upgraded its measurement facility infrastructure by acquiring a broadband Agilent microwave source which was purchased using combined funds. The MW source will be used for cutting-edge experiments in the dilution fridge, which is already set up with high frequency (up to 60 GHz) coaxial lines. This piece of equipment will prove essential for spin spectroscopy studies involving defects in semiconductors, such as silicon, III-V nanowires, quantum dots and NV- diamond devices. The closed-cycle, cryogen-free dilution refrigerator from Leiden Cryogenics (The Netherlands) was installed and commissioned in 2011. It cools a mixing chamber plate of 30cm diameter to a base temperature of 20 mK, which provides a versatile piece of real-estate to measure a number of devices simultaneously and in one cool-down cycle. The insert is equipped with 48x DC wires, 10x flexible (<1 GHz) and 2x semi-rigid coaxes (60 GHz). The system also comes with an insertable probe to ‘quickly’ characterize electronic devices at low temperatures while maintaining a low temperature of the fridge. The probe has 36x DC wires and 2x flexible coaxes and positions the samples directly into the center of a 3D superconducting vector magnet (9-1-1 Tesla) for magneto-transport and/or anisotropy studies. Furthermore, optical windows can be fitted in the outer and inner vacuum cans to illuminate devices mounted on the probe with external light sources. Cryogenic low-pass filters and breakout boxes were constructed for signal optimization and interfacing the wiring of the probe to room temperature low-noise electronics.

Optical Quantum Measurement System

The quantum sensing lab was established in 2010 and hosts three custom-built confocal microscopes as well as four wide-field microscopes, dedicated to quantum sensing and imaging based on spin defects in diamond. All microscopes are equipped with green excitation lasers, single photon counting detectors (Excelitas) or sCMOS cameras (Andor), microwave generators, static magnetic field alignment stages, and advanced electronic instrumentation for quantum control and time-resolved measurements. A custom-built interface allows the user to implement a variety of quantum measurements on single or multiple spins, which is used for various applications such as detecting ions in solution, performing magnetic resonance spectroscopy of nanoscale volumes, or imaging two-dimensional materials. In addition, one of the wide-field microscopes is fitted with an environmental control system that allows adjustment of temperature (from room temperature up to 37 ̊C), humidity and CO2 level (Clear state solutions). This system is used to image the magnetic properties of biological samples in their native environment (in-vitro), with a sub-micrometre diffraction-limited resolution. Finally, one of the confocal systems is combined with an atomic force microscope (Asylum Research), allowing scanning spin experiments to be performed with nanometer scale resolution.