Optical Components
Optical Mirrors are optical components designed to reflect light of a given wavelength range. According to the different intentions of designs, the shape of the mirror also varies. Optical mirrors could be flat or curved (convex or concave), or wedged. Usually, optical mirrors are developed based on glass subtrates and optical coatings; the thin film coatings ideally have high reflectivities and at the designed spectrum, polarization, and incidence angles, or the coatings could also be partially reflective.
Classified according to coating materials, optical mirrors can be divided into dielectric mirrors and metallic mirrors. Dielectric mirrors utilize a dielectric coating stack of multiple thin films to achieve high reflectance and an excellent laser-induced damage threshold. Most laser mirrors are dielectric mirrors. In comparison, metallic mirrors have lower reflectivities across a broader wavelength range. Metallic mirrors can also be combined with a dielectric coating to enhance the reflectance or protect the metal coating.
When the reflective coating is deposited on the front surface of optical mirrors, that is to say, the incoming light directly incident on the reflective surface without propagating through the glass substrate, the optical mirror is referred as first surface mirror, most laser mirrors are first surface mirrors; when the reflective coating is coated on the backside, the mirror is called a second surface mirror. Most dielectric mirrors are first surface mirrors to avoid unwanted reflections, while most metallic mirrors are second surface mirrors to protect the subtle metal coating surface.
Optical mirrors are devised to control the direction of light beams, folding the optical path, or changing the spectral characteristics or polarization states of light. For example, laser output couplers are used in laser cavities to acquire a stable output of laser beams, and dichroic mirrors are used as harmonic separators to separate the harmonic generated wavelength and fundamental wavelength of the laser gain media. At its core, optical mirrors provide reflective planes that interact with incident light, causing it to change direction according to the laws of reflection and refraction. The choice of substrate materials, optical coatings, and geometrical configurations determines the mirror's functions. Optical mirrors are indispensable components in a diverse range of industries and applications, such as medical, semiconductors, astronomy, life science, and metrology.
Hangzhou Shalom EO offers a wide range of off-the-shelf and custom optical mirrors and laser mirrors. The mirrors can be dielectric mirrors or metallic mirrors (enhanced Al-coated mirrors, protective silver/gold coated mirrors). For different applications, we provide the following mirror types:
1. Laser line mirrors:
Both narrowband laser line mirrors and broadband laser line mirrors are available. These are dielectric-coated reflectors with high reflections to laser wavelengths, oriented for Nd:YAG, diode lasers, Ti:Sapphire lasers, etc. The mirrors are made of Corning 7980 substrates.
2. Output couplers
These are partially reflective cavity laser mirrors with diverse design wavelengths ranging from 532nm to 1645nm.
3. High power laser mirrors
Various types of optical mirrors with high laser induced damage threshold for high-power laser systems are available.
4. Metallic Mirrors
Including aluminum coating for UV to visible spectrum, silver coating for visible to near-infrared spectrum, and gold coating for infrared spectrum. The mirrors can be either made of N-BK7 or UVFS substrates
5. Femtoline low GDD mirrors
These mirrors feature low group delay dispersion optimized for femtosecond lasers.
6. Ultrafast-enhanced silver mirrors
These mirrors also controlled dispersion, which is essential for ultrafast lasers. Compared to femtoline dielectric mirrors, ultrafast enhanced silver mirrors have lower reflectance but broader spectral coverage.
7. Dichroic mirror (harmonic separators)
Shalom EO provides ultrafast harmonic separators, which are dielectric beamsplitter mirrors designed for femtosecond lasers; the mirrors have high reflection to one wavelength, and high transmission for another wavelength for nonlinear frequency conversions.
Shalom EO’s optical mirrors and laser mirrors cater to applications in the UV, Visible, and IR spectral ranges. The mirrors consist of engineered dielectric coatings or metallic coatings deposited on durable glass substrates such as Corning 7980 (a glass material renowned for low thermal expansion), resulting in high reflectivities over various broadband spectra or laser line wavelengths. Stocked and custom optical mirrors are available. One of our know-how is the manufacturing of high-precision optical mirror substrates and the fabrication of optical coatings using our Ion-assisted e-beam coating technologies. The coatings are fabricated using Shalom EO’s SHINCRON MIC-1350TBN coating machine and tested using PerkinElmer Lambda 1050+ spectrometer.
The mirrors feature superior surface quality and high damage thresholds. We have succeeded in developing high power laser mirrors with a laser damage threshold of >20J/cm2@1064nm, 10ns, 10Hz pulses. Chirped mirrors for dispersion compensation of ultrafast lasers or femtosecond lasers are also available. Super Polished Mirror and Mirror Substrates with <1 Angstrom roughness are also provided.
1. Reflectivities: Reflectivities are affected by absorption loss, scattering loss, and transmission loss.
2. Angle of Incidence (AOI)
3. Laser Induced Damage Thresholds (LIDT) (important if you are buying a laser mirror for high power laser systems)
4. Polarization
5. Chromatic Dispersion: dispersion is a critical factor in femtosecond lasers and ultrafast lasers, as it will affect the pulse shape. A common parameter used to quantify chromatic dispersion is group delay dispersion (GDD), measured in fs^2.
