The linear variable edge filter has an interference film layer deliberately wedged in one direction, which is used to create a linear shift in the central wavelength over the entire length of the substrate. This shift makes the filtering range of the filter wider, that is, the functions of linear variable short-wavelength pass, long-wavelength pass and birefringence edge filters.
Short-wavelength pass and long-wavelength pass edge filters operate in opposite ways; the short-wavelength pass filter allows light to pass through the entire length of the filter until it encounters the cutoff band; while the long-wavelength pass filter blocks the light until it encounters the transmission band. Users can reorient the filter relative to the light source to adjust the cutoff band and transmission band.
With its wide cutoff and transmission range, a single linear variable edge filter can replace an entire set of filters. When it is synchronized with a single moving grating spectrometer, the combined use of short-wave-pass and long-wave-pass edge filters will be able to reduce discrete light and harmonics. Moreover, the combined use of linear variable filters can be used as a single variable excitation filter in various fluorescence applications that use white light sources
Ultraopto’s Linear Gradient Filter is a high-resolution spectral optical filter engineered with advanced ion-assisted and ion beam sputtering coating technology, featuring spectral characteristics that vary linearly with the filter surface position to form nearly continuous spectral channels, serving as a new-generation core spectral component for hyperspectral imaging, spectral analysis and portable optical detection systems. Unlike traditional prisms and gratings, our Linear Gradient Filter is manufactured by depositing multi-layer films with linearly varying thickness on premium optical-grade glass and fused silica substrates, enabling high spectral resolution and efficient light splitting with a compact structural design, and the passband position can be arbitrarily designed according to application requirements, providing flexible spectral customization for diverse optical systems. The filter delivers a high average transmittance in the target spectral range, with low optical loss and minimal chromatic aberration, ensuring high-fidelity spectral signal transmission and accurate spectral detection, and its nearly continuous spectral channels enable the capture of fine spectral information that traditional fixed-band filters cannot provide, meeting the high-resolution spectral analysis needs of modern optical technology.
We implement strict precision coating and substrate processing technology, achieving uniform linear variation of spectral characteristics across the filter surface, with a superior surface quality and a clear aperture of over 90%, minimizing light scattering and reflection loss for optimal optical performance. The filter features an ultra-compact and lightweight design, with a much smaller volume and weight compared to traditional prism and grating spectrometers, enabling the miniaturization and integration of spectral analysis systems, and it can be combined with CCD/CMOS detector arrays to form a spectral recognition detector, greatly simplifying the structural design of optical systems, improving the reliability and stability of instruments, and reducing the overall R&D and manufacturing costs of spectral equipment. The durable hard coatings exhibit excellent environmental stability, with scratch resistance, temperature change resistance and humidity resistance, ensuring long-term stable operation in both laboratory precision testing and harsh outdoor field detection conditions, and the filter has a long service life with no need for frequent calibration and maintenance.
Ultraopto’s Linear Gradient Filter is widely applied in a broad range of professional optical fields that demand high-resolution spectral analysis and compact system design, including hyperspectral imaging for capturing high-resolution spectral images of biological samples, industrial materials and the Earth’s surface to achieve precise material identification, surface defect detection and environmental monitoring. In atmospheric monitoring, it is used for real-time detection of atmospheric trace gases, particulate matter and air quality, providing accurate spectral data for environmental protection and meteorological forecasting, and in food safety testing, it enables rapid non-destructive detection of food composition, freshness and harmful substance content, ensuring food safety and quality control. It also serves as a core component in aerospace remote sensing for spectral detection of the Earth’s surface and atmosphere from space, in biomedical fluid analysis for non-invasive detection of biological fluid components and disease diagnosis, and in industrial process monitoring for real-time spectral detection of industrial production processes and product quality control. Additionally, the filter is used in portable spectrometers for on-site field detection, in laser system design for grating secondary light separation and cutoff, and in academic research and optical experiment platforms for spectral analysis and new material development.
As a leading manufacturer of precision linear gradient optical filters, Ultraopto offers fully customized Linear Gradient Filter solutions to meet your unique spectral and application requirements. Our professional R&D and engineering team can tailor the spectral range, spectral resolution, passband position and filter dimensions, with ultra-strict tolerance control for the linear variation of spectral characteristics to ensure high spectral resolution and accurate spectral detection. We also provide custom substrate material selection (optical-grade glass, fused silica, etc.) and coating designs optimized for specific spectral ranges (UV, visible, infrared), as well as custom processing for combination with CCD/CMOS detector arrays to achieve seamless integration into your spectral detection systems.
All custom Linear Gradient Filter orders undergo multi-stage strict optical performance testing and quality inspection, including transmittance measurement, spectral resolution testing, linear variation verification of spectral characteristics and environmental stability testing, with a detailed quality inspection report provided to ensure the final product fully complies with your design specifications and application needs. Backed by advanced multi-layer gradient coating technology, rich experience in spectral filter design and a complete quality control system, Ultraopto ensures stable batch supply capacity and consistent product quality, providing global customers with high-quality Linear Gradient Filter products and one-stop spectral optical solutions. For more detailed technical parameters, product quotation information or custom design solutions for our Ultraopto Linear Gradient Filter, please contact our professional sales and technical team through the official website, and we will provide you with efficient, personalized and professional optical solutions to support the development and optimization of your high-precision spectral analysis systems and portable detection equipment.
