Low Cost SWIR Options

IMVE publishes an article "Saving on SWIR" talks about cheaper than InGaAs option for SWIR imaging. One of them is Imec quantum dots:

"Quantum dots are nanocrystals that, depending on their size, offer different light absorption properties. For example, particles approximately 3nm in size absorb at 940nm, while particles around 5.5nm in size absorb at 1,450nm. The pixel stacks of the new sensor can be tuned to target a spectrum from visible light all the way up to 2µm wavelength.

‘Right now there isn’t much of a SWIR imaging market, because there is such a high [price] threshold for acquiring a SWIR camera,’ said [Pawel Malinowski, Imec’s thin-film imagers programme manager.] ‘In a lot of machine vision applications people are not using SWIR because they cannot get a camera, so what we are hoping for is that because we can offer SWIR imaging at orders of magnitude lower price, then new applications will pop up.’

The first generation of Imec’s quantum dot sensor has a resolution of 758 x 512 pixels and a pixel pitch of 5µm. According to Malinowski, however, the second-generation chips, currently being tested, will have a pixel pitch as low as 1.8μm. He noted that the typical pixel pitch of an InGaAs sensor is between 15μm and 20μm.

Despite the lower fabrication cost and higher resolutions achievable with the new sensor technology, Malinowski said quantum efficiency – the performance achieved for the amount of light – will only be around 30 to 40 per cent; InGaAs sensors are able to offer 80 to 90 per cent quantum efficiency. He added: ‘I think that InGaAs will remain unbeatable in terms of high-end performance for the time being."

SWIR Vision company too pursues quantum dots:

"Quantum dot-based SWIR imaging technologies are also available from US-based SWIR Vision Systems, which has been selling its Acuros colloidal quantum dot (CQD) VIS-SWIR cameras from Q3 2018. The cameras are available in VGA (640 x 512 pixels), one-megapixel (1,280 x 1024 pixels), and full HD (1,920 x 1,080 pixels) formats.

‘Demand for these cameras has been increasing throughout 2019,’ said George Wildeman, CEO of SWIR Vision Systems, who remarked that the 1,920 x 1,080-pixel model, which has a resolution six times higher than the current standard 640 x 512-pixel InGaAs cameras, is the first of its kind to be commercially available. ‘There are a few high-resolution InGaAs cameras with 1,280 x 1,024-pixel sensor arrays, but these are very high cost,’ he said. ‘It is a big challenge to scale InGaAs cameras to larger array sizes without a large increase in their price point.’

Yet another option is Emberion graphene imagers:

"The first product samples of the sensor, which offers VGA resolution, 20µm pixel pitch, 100fps frame rate, and a spectral range from 400nm to 2,000nm, will be available in June 2020.

‘This wide spectral range is the key advantage that our sensor provides over standard InGaAs sensors, which tend to go between 900nm to 1,700nm,’ said Jyri Hämäläinen, director of sales and marketing at Emberion. ‘Beyond 1,700nm is usually called “extended InGaAs”, and it is here that InGaAs technology becomes very expensive. In comparison our sensor is much more affordable while being able to detect these wavelengths.’

Thanks to TL for the link!