Optical Prisms

Penta Prisms

Prisms: Bend light into specific angles. Capable of shifting light and adjusting image orientation. Design elements like shape and cementing determine prism-light interaction modes: Upon entering, light exits after reflecting off one or multiple surfaces; or refracts when passing through the substrate material.
INQUIRY

I. Common Materials

The performance of optical prisms depends heavily on the optical and mechanical properties of the materials. Common materials include:

Material Type	Characteristics & Applications
K9 Optical Glass	Refractive index 1.5168 @589.3nm, cost-effective, widely used in visible spectrum (e.g., laser pointers, educational instruments).
Fused Silica	UV-NIR transmission (185nm-2.1μm), low thermal expansion, suitable for high-power laser systems (e.g., CO₂ laser cutting heads).
N-BK7 Optical Glass	Low bubble impurities, high homogeneity, ideal for precision imaging systems (e.g., microscope objectives, telescopes).
Calcium Fluoride (CaF₂)	High UV/IR transmission (0.15μm-8μm), low dispersion, used in deep UV lithography and IR spectrometers.

II. Structural Shapes & Functions

Prism shapes determine optical behavior. Common types and functions:

Type	Structural Features	Core Functions
Right-Angle Prism	90° triangular shape, total internal reflection on hypotenuse	90° beam deflection, image rotation (e.g., laser engraver light path folding).
Pentagonal Prism	Five-sided structure with two reflections	Constant 90° deflection independent of input angle (e.g., rangefinders, military targeting systems).
Rhomboid Prism	Parallelogram cross-section	Beam displacement without angular deviation (e.g., interferometer path compensation).
Roof Prism	Right-angle prism with roof-shaped reflecting surfaces	Image inversion + beam steering (e.g., binocular image correction).
Beamsplitter Prism	Hypotenuse coated with beamsplitting film	Proportional beam energy division (e.g., laser splitting, 3D sensing).

III. Machining Accuracy Requirements

Prism performance is directly influenced by machining precision. Key parameters include:

1. Geometric Accuracy

◦ Dimensional Tolerance: ±0.01mm (up to ±0.005mm for high-precision applications)

◦ Angular Deviation: <3 arcmin (military-grade: <1 arcmin; 1 arcmin = 1/60 degree)

◦ Surface Flatness: λ/8 @632.8nm (λ = laser wavelength)

2. Surface Quality

◦ Scratch-Dig Standard: 20-10 (scratch width ≤20μm, dig diameter ≤0.1mm)

◦ Roughness: Ra<1nm (ultra-smooth surfaces for UV laser systems)

3. Coating Requirements

◦ Anti-Reflective (AR) Coating: Single-wavelength residual reflectance <0.2%, broadband (400-700nm) residual reflectance <0.5%

◦ High-Reflective (HR) Coating: Reflectance >99.8%@specific wavelengths (e.g., 1064nm lasers)

IV. Core Optical Properties

1. Refraction & Dispersion

◦ Refractive Index (n): Determines beam deflection angle (e.g., K9 glass with n=1.517 produces 28° refraction angle at 45° incidence).

◦ Abbe Number (Vd): Measures dispersion strength; higher Vd = lower dispersion (N-BK7: Vd=64.2).

2. Total Internal Reflection

◦ Critical Angle Formula: θ_c = arcsin(n2/n1), used in right-angle prisms for efficient beam steering.

3. Polarization Properties

◦ Brewster Angle Design: Eliminates reflective polarization loss (e.g., Brewster windows in laser cavities).

4. Beamsplitting Properties

◦ Adjustable Splitting Ratio: 50:50 (equal splitting) or custom ratios (e.g., 80:20 energy distribution).

V. Typical Applications in Optics

Application Field Usage Scenarios & Prism Types

Laser Technology - Beam expansion: Prism pairs (e.g., Nd:YAG laser processors)

- Pulse compression: Fused silica prism pairs (femtosecond lasers).

Imaging Systems - Image correction: Roof prisms (DSLR viewfinders)

- Confocal scanning: Polygonal scanning prisms (biological microscopes).

Spectral Analysis - Dispersion: Constant deviation prisms (Raman spectrometers)

- Wavelength selection: Beamsplitter prisms (fluorescence detectors).

Fiber Optics - Optical coupling: Right-angle prisms (fiber collimators)

- WDM: Coated beamsplitter prisms (DWDM modules).

Precision Metrology - Interferometry: Cube beamsplitter prisms (laser interferometers)

- Angular reference: Pentagonal prisms (aerospace attitude calibration).

Medical Devices - Endoscopic imaging: Micro prism arrays (electronic endoscopes)

- Laser therapy: High LIDT prisms (ophthalmic femtosecond lasers).

The above descriptions serve as a foundational framework for product specifications. Customize with actual test data (e.g., interferometer reports, laser-induced damage threshold results) and industry certifications (ISO 10110 optical drawing standards).