This article reflects the opinion and analysis as well as information collated by AE Research Management Sdn Bhd, and does not constitute an investment advice or recommendation
Light Sciences Basic
In the electromagnetic spectrum, light waves typically refer to the zone encompassing X-ray, ultraviolet, visible light, and up to the infrared territory (see graphic). This zone straddles wavelength as short as 10 picometers to as long as 1 millimeter.
Source: NASA’s Imagine The Universe
The characteristics of light vary at different wavelengths, and scientific research to understand the various properties are still broadening.
Underexplored frontiers include the Terahertz zone – region between light and radio waves – which may offer many potentials because it has properties of both light and radio waves.
The properties of light across the electromagnetic spectrum are harnessed to enable many innovations which bring benefits to the society.
Progress is founded on material chemistry and physics – capabilities required to develop light sources of sufficient high output power at desired wavelength(s). Typical light wave generation include through vapor/gas discharge, molecules excitation, electrons acceleration, as well as from wide-bandgap compound semiconductors.
In particular, there are not many light sciences companies with deep R&D expertise into group 13 & 15 elements of the periodic table – indium (In), phosphorus (P), aluminum (Al), gallium (Ga), arsenic (As), nitrogen (N) et al – as light source materials for photodiodes.
Advanced Applications of Light – examples
Light sources are in turn incorporated into instruments that exercise control over the light waves, for use as tools.
For example, the shorter wavelength X-ray and ultraviolet light, are used in medical and precision industrial applications. In the medical space, X-ray light sources are elemental in CT scan for diagnostic imaging and in radiotherapy for cancer treatment.
A notable industrial breakthrough has been in next generation semiconductor patterning. The current mainstream system based on ArF (193nm) light source is nearing its scientific limits. Mass production of sub-10nm semiconductor circuits will require the use of stable high output EUV (extreme ultra violet) light sources for lithography and defects inspection. Only 2-3 suppliers are able to meet the demanding specifications, using plasma-based technologies.
Light waves applications at the infrared/near-infrared zone are found in fiber optic communication network, and in optical sensing & measurement for transportation – LiDAR (light detection and ranging) laser diodes for advanced driver assistance system for eg. – and military purposes.
Near-infrared waves are also used in medical examination with less radiation risks than conventional equipment – for example, optical mammography based on near-infrared spectroscopy.
Deep UV – Mitigating Covid19 Risk
While vaccines for coronavirus have made headlines much of this year, little is mentioned of the effectiveness of Deep UV (ultra-violet) light in sterilizing airborne pathogens including the SARS-CoV-2 virus.
On this front, a Japan-based company which has worked on Deep-UV LED (light emitting diodes) technologies for almost two decades, has successfully introduced LEDs with luminous wavelength of 250 – 280 nm at world’s highest luminescence intensity, via improvements in AlGaN crystal growth techniques.
Merging this breakthrough with its expertise in flow mechanics, the company has commercialized air purifier systems that is capable of inactivating airborne coronavirus. A drawback of the 250 nm deep UV is the hazard it poses to human eyes and skin, thus not suitable for lighting use.
Research has shown that Deep UV in the zone of 207-222 nm will not harm the skin. While no LED is yet available in this range, excimer lamps emitting 222 nm light waves has been introduced by another company for lighting applications.