定义：
光学计量测试包括的范围相当广泛，目前国家已在许多方面建立了计量标准和测试手段。主要包括：光度、光谱光度、色度、辐射度、激光参数、光学材料参数、光学薄膜参数、成像光学、微光像增强器及夜视仪器参数、光纤和光通信函数、光电子器件参数等计量测试。

测试介绍
      光度量是限于人眼能够见到的一部分辐射量，是通过人眼的视觉效果去衡量的，人眼的视觉效果对各种波长是不同的，通常用V（λ）表示，定义为人眼视觉函数或光谱光视效率。因此，光度量不是一个纯粹的物理量，而是一个与人眼视觉有关的生理、心理物理量。
      光度计量测试的主要参数有发光强度、亮度、照度及光通量等。发光强度的单位为坎德拉（cd），是国际单位制中的7个基本单位之一，它是不可能从其他单位直接导出的。有了坎德拉基本单位的定义，即可导出光亮、光通量及光源产生的照度和色度等单位。

测试分类
光谱光度、色度计量测试
    光谱光度计量测试主要研究物质的吸收（透射）、反射、荧光和发射光谱，其主要计量测试参数有光谱规则反射比、漫反射比、光谱规则透射比、漫透射比；光谱吸收比；偏振器的消光比等。测量仪器主要有分光光度计、反射光谱仪、荧光光谱仪和摄谱仪等。
　　色度计量测试是指对颜色量值的计量测试。它是以三基色原理为基础，测出颜色的三刺激值，经计算可得到颜色的量值。
　　色度计量分为光源色和物体色两种，对光源色的计量实际上就是对光源的相对光谱功率分布的计量；对不发光的物体的透射样品或反射样品的色度计量，则是对样品的光谱透射比和光谱反射比的计量，通常使用的色度计量器具主要有标准色板、色度计、色差计以及光谱光度计等。

辐射度计量测试
       辐射度计量测试主要是在整个光谱范围内进行辐射能量和辐射功率的测量。在光辐射计量中，不再包含人的视觉因素影响，而是把光作为一种电磁辐射进行测量。
　　光辐射的计量范围较宽，包括的波长范围从紫外、可见直到红外。其主要计量参数有辐射通量、辐射强度、辐射亮度、辐射出射度和辐射照度。
　　辐射计量的标准有两种形式，一种是标准辐射源，另一种是标准探测器。标准辐射源是基于黑体辐射的理论，即黑体的面辐射度Mc与绝对温度T之间有下列关系：
　　Mc=σT4 （式中，σ-----波耳兹曼常数）
　　光辐射计量的另一种标准是标准探测器。近年来，美国国家标准与技术研究院（NIST）和英国国家物理实验室（NPL）利用硅光电二极管自校准技术，用二极管的内量子效率作为光辐射测量标准，达到了很好的不确定度。

Definition: the science and technology of performing measurements with light

More specific term: frequency metrology

Optical metrology is the science and technology concerning measurements with light. Such measurements can either target properties of light and light sources or properties of objects such as dimensions, distances and temperatures. There is no strict boundary between those fields, because often one uses measured properties of light not just to characterize a light source, but for other purposes – for example, optical frequency metrology is used for ultraprecise optical clocks.

Some examples of optical metrology are:

• Optical distance measurements with lasers can be based on, e.g., interferometers or measurements of the time-of-flight of light pulses. This is an example for dimensional metrology.
• Highly precise angular measurements are possible with autocollimators, particularly with electronic autocollimators based on lasers.
• Optical profilometers are widely used for measuring surface topographies, e.g. in semiconductor chip production and for the quality control in optical fabrication. Form metrology also uses various other kinds of instruments for measuring surface shape (contour) and surface roughness.
• Optical time-domain reflectometers are used for inspecting fiber-optic links – for example, finding faulty fiber splices or fiber connectors. Free-space reflectometers are used e.g. for characterizing thin-film optical devices.
• optical powers can be measured with photodiodes, thermal power meters, or other equipment. Optical irradiance and other illumination measurements can address either some pure physical quantity such as an optical intensity (power per unit area) (radiometry) or something like a perceived brightness (photometry). Integrating spheres are utilized for radiation emitted in a wide range of direction.
• Spectral optical properties are measured with devices like spectrographs or other spectrometers, wavemeters and self-heterodyne setups.
• Optical frequency metrology deals with high-precision measurements of optical frequencies. One can produce ultraprecise optical clocks, surpassing the performance of cesium atomic clocks.
• Optical temperature sensors may be based on the analysis of the thermal emission of hot bodies, or rely on the measurement of occupation probabilities for energy levels of atoms or molecules.
• Fiber-optic temperature and strain sensors allow for distributed sensing, often of temperature and strain combined. They can be used, for example, for measurements in industrial processing plants, bridges and tunnels, buildings, oil and gas pipelines and power transmission lines.

Optical metrology uses a wide range of measurement instruments. For calibrating those, special calibration light sources are required, providing light with well-defined properties like optical power, luminance or wavelength, for example. For example, there are certain spectral lamps providing quasi-monochromatic light with a precisely defined wavelength.

Typical Qualities of Optical Metrology

In many cases, optical metrology can be extremely precise and is ultimately limited by laser noise or quantum noise in detection.

Optical measurements are usually quite fast and suitable e.g. for in-process metrology, i.e., for monitoring industrial production processes.

Generally, optical measurements are non-destructive. Even very sensitive parts can be checked without touching them (non-contact methods), i.e., without a risk of damage.

Special Challenges

Obviously, optical metrology becomes particularly challenging when extremely high precision is required. However, the magnitude of that challenge also depends on the circumstances. For example, particularly sophisticated metrology is required for characterizing very large optics. Some traditional techniques can they not be used or need to be specially adapted.