Silicon Lenses with Large Sag

Xi'an, China – [January 6th, 2023] – Focuslight Technologies Inc., a global provider of high-power diode lasers and micro-optics, has announced Silicon Lenses with Large Sag.  

 Silicon Lenses Wafer   

Silicon lenses have been widely used in a variety of infrared applications operating in the 1.2 - 7 μm wavelength range such as NIR imaging, biomedical and radiation sensing, with the advantages of high refractive index (n=3.4), hard material resistance, and low temperature sensitivity.  Due to its low density (2.329 g/cm3), silicon lenses are ideal for weight-sensitive applications.  

The typical processing technologies of silicon lenses are etching or CNC machining, resulting in the typical lens sag value of <60 µm.  At Focuslight, optical components are manufactured on a wafer base with Focuslight’s own wafer-level simultaneous structuring technology, which is applicable to any kind of inorganic optical material. From CaF2 and MgF2 crystals, to high-grade fused silica or high-index glasses, to semiconductor-industry quality Si and Ge material, the wafer-based products cover a wide range of wavelengths from DUV to FIR, structuring optics with nearly unlimited complexity of 1D acylindrical and prismatic surface geometries. Especially (but not exclusively) for silicon, this includes optical and mechanical features for alignment and assembly, opening up the opportunity to implement the products for optomechanical and optoelectronical functionalities. With this processing technology, the lens sag can achieve as large as 4 mm (4000 µm) at an exit angle of 0°~80° on silicon lenses, which maximizes the numerical aperture (NA) that a silicon lenses could achieve and exceeds the limit of the silicon lenses processed with conventional technologies. This enables products that have been hard or impossible to be produced by classical lithographical technologies, such as deep-sag decentered lenses, blazed gratings, chirped arrays or integrated prisms.  

Symmetric and Asymmetric Microstructures Processed by Focuslight Wafer-level Simultaneous Structuring Technology 

As our Product Line Manager of Laser Optics Business Unit Dr. Daniel Braam states: “The possibilities are almost unlimited – we offer a technology that is capable of making unique optical solutions to drive revolutionary applications. Now we have extended this to silicon, creating a new building block for a wide range of next generation silicon photonics, enabling biosensing, PICs, and much more.” 

Focuslight wafer-based production technology produces polished wafers up to 300 x 300 mm², making it possible to produce tens of thousands of lenses in a two-step process with a consistently high level of quality. It is a scalable and cost-effective production technology for very high quantities, making it affordable for massive applications such as IoT,  biosensing, smart terminals, etc. The advantages of unique performance and cost structure of this technology have been well demonstrated by Focuslight being a dominant Fast Axis Collimator (FAC) supplier for fiber laser pumping market with over 20 million pieces shipment per year. 

300 mm x 300 mm wafer produced with wafer-level simultaneous structuring technology 

Silicon lenses typically have low transmission efficiency without AR coating. A precise and optimized design of a proper coating recipe for silicon lenses and production process of optical coating can ensure good product performance and long-term operational reliability. Focuslight has in-house capability to design, manufacture and supply high quality coatings for optical communications, instrumentation, and medical applications, as well as conducting thin film analysis and measurement. A wide variety of coatings to cover the wavelength range from the deep ultraviolet (DUV) to infrared (IR) can be customized.  

AR coating available up to R<0.2% and bandwidth up to 1200nm.

About Focuslight Technologies 

Founded in 2007 and headquartered in Xi'an, China, Focuslight Technologies Inc. is a fast-growing company that develops and manufactures high power diode lasers (photon generation), laser optics (photon control), and photonic modules and systems (application solutions) used in advanced manufacturing, health, research, automotive, and consumer electronics applications. In 2017, Focuslight acquired LIMO, one of the leading manufacturers of micro-optics and beam shaping solutions, and a pioneer in groundbreaking photonics production technologies. Focuslight has over 400 patents worldwide and is ISO 14001, ISO 45001, ISO 9001:2015, and IATF 16949 certified. Additional information can be found at www.focuslight.com.