Light microscopy requires a light source, laser, lamp, LEDs, to illuminate a surface. The reflected or transmitted image is captured by an optical imaging chip, or your eyes. In ultrasonic imaging, ultrasonic wave pulses are generated by piezoelectric transducers from MHZ to GHz frequencies. The wave packets travel through a substrate, and reflect off the imaging surface, and are measured electronically by the receive transducer. The transmitter and receiver are integrated in one chip in Geegah imagers.
Ultrasound means sound waves that are operating at high frequencies, outside the audible frequency range. Typically, anything above 20kHz is considered ultrasound. However, for Geegah, our devices operate at the very high imaging frequencies of several Gigahertz (billion cycles per second)
For Geegah imager, gigahertz ultrasonic wave pulses are generated by thin piezoelectric transducers at 1-2 GHz. The wave pulses/packets travel through the silicon substrate and reflect off the silicon-sample interface. The reflected pulses are received back at the transducers for measurement. The 128x128 pixels, we measure the received pulses, acquiring both magnitude and phase.
The answer depends on what is being imaged. GHz ultrasonic pulses decay quite fast in liquids ,within 10-50um. In solid crystals, loss is much lower, and ultrasonic pulses can travel mm to cm deep.
If a very thin film of liquid or other material is placed on the imager, the ultrasonic pulses reflected from the silicon-sample and the sample-air interface can inter, and generate Newton rings as the material evaporates.
The Geegah imager can work at a frequency range from 1-2 GHz.
Geegah imager can achieve 4-10 frames per second, enabling real time movies of the surface. However, if less number of pixels are scanned, using a ROI (Region of Interest) process, higher frame rates are possible. Can it measure temperature? What is the operating temperature range of the imager. If an object that is hot or cold is placed on the imager surface, heat diffuses into the imager silicon substrate. This can change the temperature of the substrate, which changes the phase of the return pulses. This information is readout. We can operate the device from -10 to +120C
Ultrasonic impedance of an object is a measure of the sample’s elasticity and density. The ultrasonic impedance is the square root of the elastic modulus times the density.
The imager can be connected to laptop, or a desktop though a USB cable. Geegah’s GUI (Graphical User Interface) enables easy image collection, storage, image and movie making.
Geegah also offers specialized image classification software for specific use cases.
Geegah can provide demos if you send us a sample.
Geegah imager works by imaging placing a sample on top. An optical microscope can be placed on looking at the top side of the sample. Hence, optical and ultrasonic images can be recorded simultaneously.