Introducing HaloMicroscopy
What is Resonance Imaging Microscopy ?
The HaloElement allows users to detect and image particles, materials, cells, bacteria, crystals, capsules, histology sections. It can also image opaque samples such as semiconductors, fibres, polymer films, bank-notes and metal particles, in air or in liquid.
Key features of the HaloElement include:
- Laser free and non-destructive process;
- No labels, dyes or stains are required;
- Size range 10’s of nanometres up to millimetre scale;
- Acquires images as fast as you can take a picture;
- Simple sample handling, using a glass slide, cover slip with liquids, in air, or a petri dish;
- Integrates with off the shelf heating stages and flow cells for live-cell imaging;
- The resultant data and image is owned by you.
Underpinned by the discovery of Resonance Imaging Microscopy (RIM) at the University of Melbourne, the HaloElement employs this patented technology to create an Evanescent Wave (EW), used to illuminate samples from the side rather than vertically.
A ring on LEDs surrounding the sample is used to generate an EW via total internal reflection at the solid-air or solid-liquid interface. When at least a portion of the sample interacts with the EW, the EW scatters or resonates within the object. The resultant light, scattered by the sample, is detected by conventional light microscopy methods and a composite image is created.
What is a Hot Spot ?
Seen most easily for simple objects of any shape, e.g. spheres, rods, prisms, etc. , when the object frustrates the EW, the resulting scattering appears as edge localised hot spots when using an appropriate NA objective. Since EW’s are not diffraction limited, these hot spots can be used to find the edges or detect particles well below the diffraction limit of approximately 200nm.
Above, Left A particle interacting with an EW. Inset a single hot spot on a particle edge in a brightfield microscopy image.
Above, Right A HaloImage of 5 micron diameter polystyrene particles where the hot spots trace the edge of the particles using a faux colour scheme.
Left, Top Side view of a HaloElement schematic with cutaway showing the delivery of the EW using LED light sources. Left, Bottom Top view of the schematic where the bold red lines represent the light originating from the circular array of LED sources.
What is a HaloImage ?
The HaloElement takes a sequential series of frames and combines them to form a composite image or scene called a HaloImage. A faux colour scheme is used to encode the spatial or angular orientation of each LED source with respect to the sample (like the locations on a clock face). The frames are combined into a single composite HaloImage as shown below (lower right) for a 50 nm tall gold pattern deposited on glass, made via electron beam lithography.
Edge Detection
A key feature of HaloMicroscopy is that it will reveal where changes in structure occur at the boundary between one material and the next.
The contrast shown in HaloMicroscopy originates, in part, from the differences in refractive index within the sample. For isotropic materials such as simple particles, isotropic films or samples with large void regions, the edges of the object will be highlighted in the HaloImage.
The inner regions of a material will appear dark, unless they contains other structures, with a different refractive index.
HaloImage and brightfield image for a nanofabricated pattern formed by depositing a 50 nm thick gold film. The HaloImage shows that the regions inside the boundaries are uniform, as there are no defects detected
HaloImage and brightfield image of 5 mm polystyrene particles. The hotspots define the edges of the particles.
HaloImage and brightfield image of Lilium (lily) stem section where the HaloImage highlights the edges or walls of the stem.