Ion Beam Sputtering Coating Deposition Facility
Notch Optics operates a state-of-the-art facility for high-quality optical coating production. The core of this facility are 16 large-chamber ion beam sputtering deposition systems.
The coating system features an ellipsometric optical monitoring system, allowing for precise control of coating thickness during deposition. Additionally, post-deposition annealing is available for large optics up to 34 cm in diameter, and can be performed in vacuum, inert atmospheres, or air.
The facility is also equipped with cutting-edge inspection devices such as ellipsometers, photospectrometers, and precision measurement systems for assessing absorption, transmission, and reflection properties of the coatings.
How Does an Ion Beam Sputtering Coating Machine Work?
An ion beam sputtering (IBS) optical thin film coating machine is a highly precise system used to deposit thin films onto optical substrates. It is widely recognized for producing high-quality coatings with excellent uniformity, low roughness, and high durability, often used in demanding applications like lasers, mirrors, and sensors. Here's how the machine works:
1. Ion Beam Generation
The process begins with the generation of an ion beam. An ion source (typically argon gas) is accelerated using electric or magnetic fields, creating a beam of high-energy ions. These ions are directed towards a target material (the coating material) inside a vacuum chamber.
2. Sputtering of the Target Material
When the high-energy ions strike the surface of the target material (usually a metal, dielectric, or oxide), they transfer their energy to the atoms of the target. This causes the surface atoms of the target to be ejected or "sputtered" away in a process known as sputtering. The sputtered atoms are then released into the vacuum chamber.
3. Deposition onto the Substrate
The ejected atoms from the target material travel across the vacuum chamber and deposit onto the substrate (the optical element to be coated), forming a thin film layer. Since the ion beam is highly focused and controlled, this method ensures that the coating is applied with extreme precision, providing excellent film uniformity and smoothness.
4. Precision Monitoring and Control
Ion beam sputtering systems often use optical monitoring systems, such as ellipsometry, to precisely measure and control the thickness of the growing coating layer in real time. This allows for highly accurate deposition of layers with controlled thickness, which is crucial for achieving the desired optical properties of the thin film (e.g., anti-reflective, reflective, or filter coatings).
5. Post-Deposition Treatment
Some IBS systems are equipped with post-deposition annealing capabilities. After the thin film is deposited, the coating may be heat-treated (annealed) to improve its adhesion, densify the layers, or optimize its optical performance. Annealing can be performed in different environments, such as vacuum, inert gases, or air, depending on the specific requirements of the coating.
6. Benefits of Ion Beam Sputtering
- High Film Density: The energetic ion bombardment during deposition leads to coatings with high density, which makes them more durable and resistant to environmental factors like humidity or temperature changes.
- Low Roughness: IBS coatings tend to have very smooth surfaces, ideal for high-precision optical applications.
- Superior Adhesion: The process creates strong bonds between the coating and substrate, which improves the film's durability and mechanical stability.
- Precise Thickness Control: The ability to control the ion beam and deposition rate results in highly accurate layer thicknesses, which is crucial for achieving desired optical properties (e.g., reflective or anti-reflective layers).
- Multi-Layer Coatings: IBS is particularly effective for creating multi-layer coatings, where each layer may have different refractive indices to enhance optical performance (e.g., mirrors, filters).
7. Applications
- Laser Optics: IBS coatings are ideal for high-power laser optics due to their high damage threshold and low absorption.
- Gravitational Wave Detectors: Used for making ultra-low-loss coatings for interferometers.
- Precision Mirrors and Filters: Producing coatings with specific reflective or transmissive properties for scientific and industrial applications.
In summary, ion beam sputtering works by bombarding a target material with high-energy ions to release atoms, which then deposit onto a substrate, forming a highly controlled, uniform, and durable thin film. This method excels in producing precision optical coatings with superior quality.
IBS Coating Capabilities
Notch Optics utilizes Ion Beam Sputtering (IBS) as its advanced deposition method for producing a wide range of thin-film coatings, offering several advantages over traditional methods.
IBS coatings are known for their exceptional density, resulting in low surface roughness and superior thermal stability.
These coatings can withstand temperatures up to 300°C for long-term exposure and 500°C for short-term exposure, with a minimal thermal shift of < 0.5 pm/°C.
This thermal stability is crucial for applications requiring precise optical performance under varying environmental conditions.
IBS coatings by Notch Optics encompass various types tailored to specific optical needs:
- AR (Anti-Reflective) Coatings: Designed to minimize Fresnel reflections across narrowband, broadband, or multiband applications.
- Dielectric Mirror Coatings: Utilize constructive interference to achieve high reflectivity over specific wavelength ranges, adaptable for narrowband, broadband, and multiband applications.
- Shortwave Pass Filters: Block longer wavelengths while allowing shorter wavelengths to pass through.
- Longwave Pass Filters: Block shorter wavelengths while transmitting longer wavelengths.
- Bandpass Filters: Pass specific wavelength ranges while blocking others, available in narrow and wide passbands.
- Dichroic Filters: Separate discrete wavelength regions, often oriented at non-normal incidence.
- Dielectric Beamsplitter Coatings: Split light into reflected and transmitted components with a specified ratio over a given wavelength range.
- Notch Filters: Reject specific wavelength regions while allowing others to pass through, complementary to bandpass filters.
Ion Beam Sputtering Coating Applications
Notch Optics deposits these IBS coatings on diverse substrates including glass, polymer, fused silica, semiconductor wafers, fiber optic components, and laser crystals such as LBO, KTP, and LiNbO3. This versatility allows for applications in various fields:
- High Power Laser Applications: Ideal for laser optics due to their high density and low loss characteristics. Notch Optics's IBS coatings can achieve extremely low reflectance (< 0.03%) for AR coatings and high reflectance (> 99.9%) for dielectric mirrors, with minimal absorption and scatter losses, making them suitable for high power laser environments.
- Medical Applications: Used in broad band dielectric mirrors for medical imaging, including scanning and intraoral mirrors. Notch Optics also produces filters for fluorescence microscopy applications, ensuring stringent optical requirements are met.
- LiDAR (Light Detection and Ranging) Applications: Essential for filters and mirrors in LiDAR systems used for mapping, GIS technology, vehicle safety features, and law enforcement applications. The precision of IBS coatings enhances the performance and reliability of these optical components.
Overall, Notch Optics's Ion Beam Sputtering coatings are characterized by their robust performance across diverse applications demanding high optical precision, durability, and thermal stability.