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Micro-Sized Optical Spectrometre
Context:
A team of researchers from the Chinese University of Hong Kong and other institutions in China recently made a new micro-sized, portable, and cost-effective optical spectrometer.
Detailed in their paper published in Nature Electronics, this spectrometer is based on an organic photodetector with a bias-tunable spectral response.
Optical Spectrometers
- Function: To measure and analyse light properties over specific portions of the electromagnetic spectrum.
- Applications: Medical diagnostics, biological analysis, material characterisation.
- Limitations of conventional spectrometers:
- Bulky: Due to complex mechanisms and advanced optical components.
- Expensive: Limits use to specialised facilities.
- New spectrometer development: Two approaches.
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- They mimic traditional spectrometers with modern devices.
- They Use arrayed photodetectors with computational algorithms.
Key Highlights:
- Miniaturised optical spectrometers could be of use in portable and wearable applications.
- Such devices are typically based on arrays of photodetectors that provide distinct spectral responses or use complex miniaturised dispersive optics.
- Researchers report a micro-sized optical spectrometer that is based on an optical-spacer-integrated photomultiplication-type organic photodetector (PM-OPD) with a bias-tunable spectral response.
- It uses a novel method to manipulate the wavelength-dependent location of photocarrier generation in photodiodes.
- This technique involves a trilayer contact composed of a transparent back contact, an optical spacer, and a back reflector.
- The team combined this contact with a Schottky diode and an organic ternary bulk heterojunction to create a PM-OPD. The recordings collected by this photodetector were then analysed using a reconstruction algorithm.
- The approach allows the computational reconstruction of an incident light spectrum from photocurrents measured under a set of different bias voltages.
- “The device, which has a footprint of 0.0004 cm², is capable of broadband operation across the entire visible wavelength with a sub-5-nm resolution.”
Implications:
- They used it to fabricate an 8 x 8 spectroscopic sensor array for hyperspectral imaging. This technique can detect the unique spectral signatures of specific objects by processing information across the electromagnetic spectrum.
- These devices might lead to the creation of advanced technologies, potentially transforming research and medical practices.
What is Electromagnetic energy?
Electromagnetic Spectrum:
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