transmissive

Transmissive is an adjective describing a material, surface, or device that permits the passage of light, sound, or other waves through it. In optics, a transmissive material allows a portion of incident light to pass through with attenuation, a property quantified by transmittance. Transmissive is often used in contrast to opaque or reflective surfaces; a transparent material transmits light with minimal scattering, while a translucent one transmits light but scatters it, reducing image clarity.

Transmittance depends on wavelength, thickness, coatings, and internal scattering. It is commonly expressed as a ratio or percentage of transmitted to incident light. Real-world materials exhibit wavelength-dependent transmittance since different wavelengths are absorbed or scattered to varying degrees. Measurements are used in applications ranging from glazing to optical coatings and fiber optics.

Applications span several fields. In displays, transmissive refers to screens that require a backlight behind the display stack so light can pass through to form an image. This contrasts with reflective displays that rely on ambient light and transflective displays that combine both backlighting and reflection. In architecture and glazing, transmissive glass and windows are designed to admit daylight while managing energy transmission, often with coatings to modify visible or infrared transmittance. In fiber optics and imaging, high transmissivity is crucial for efficient signal or image transmission.

Related concepts include transmittance, absorptance, and reflectance, which together describe how a material interacts with incident waves.