VCSELs serve advanced 3D sensing applications
VCSEL (vertical-cavity surface-emitting laser) are a perfect laser light source for 3D sensing applications in smartphones, consumer electronics, automotive as well as for industrial sensing. VCSELs are attractive as they come with a small form factor and the option to integrate various functions. Therefore, the small laser diodes offer benefits to optical engineers such as freedom. While TRUMPF already shipped more than 2 billion VCSELs to the market, product development continuously serves the demanding industries by improving illumination quality and overall performance. General trends go towards smaller and smarter components. In various industries from consumer electronics, to automotive to industrial sensing there is always a demand to reduce footprint and enhance the functionality per VCSEL chip area. TRUMPF therefore offers 3D sensing VCSEL solutions with features such as polarization, integrated lens structures or optics. Another approach to integrate functionalities are VCSELs with integrated photodiodes (ViP). ViP not only emit radiation, but it also detects signals for further processing. This enables the so called self-mixing interference technology (SMI), where a VCSEL projects an infrared laser beam onto the surface of a passing object. An optical resonator catches the reflection of the laser beam and mixes it with the light in the resonator. The photodiode measures the interference, and the system calculates the movement speed from the frequency difference. This is for example interesting for industrial laser sensors to monitor processes to detect speed and position within a production line. The SMI technology is already used in millions of products for around 20 years and proven itself, but still there are interesting new application fields such as for eye-tracking applications in VR/AR.
High-end smartphone applications are looking for constant improvements of their functionalities of laser for time-of-flight or structured light sensing technologies for applications as face recognition or laser auto focus. Additionally, there is a common trend of all-screen-display, which challenges system designers to place advanced optical sensing technologies underneath the displays. VCSELs are perfect to integrate under displays due to their vertical laser emission, minimum height and small footprint. By offering even more compact laser components, this trend is addressed to enable an even smaller footprint of the chip and therefore addressing an overall smaller building area. TRUMPF therefore offers compact VCSEL solutions with high power output at the same time. The company recently introduced a new single-mode 940 nm VCSEL array, which consists of twelve quadratic emission zones to generate a high output power of 20 mW with an absolutely symmetrical Gaussian beam shape, also at high pulsed operation.