Cuvette having high optical transmissivity and method of forming

An optical element that includes a cuvette for holding a test sample, the cuvette comprising:

• a body that includes first, second, third, and fourth surfaces, each comprising a first material that is characterized by a first refractive index for a first light signal;
• a first geometric anti-reflection (GAR) layer disposed on the first surface, the GAR layer including a first plurality of features that have substantially the same height and extend normally from the first surface, wherein each feature of the first plurality thereof extends between a first base located at the first surface and a first tip located at a first boundary, and wherein each feature of the first plurality thereof has a first cross-section that increases monotonically from the first tip to the first base, and further wherein the first boundary is characterized by a first effective refractive index that is lower than the first refractive index;
• and
• a second GAR layer comprising a second plurality of features that extend normally from the second surface, wherein each feature of the second plurality thereof extends between a second base at the second surface and a second tip, and wherein the plurality of second tips collectively defines a second boundary that is characterized by a second effective refractive index that is lower than the first refractive index.

A method for forming a cuvette for holding a test sample, the method comprising:

• providing a body having first, second, third, and fourth surfaces that comprise a first material having a first refractive index for a first light signal;
• forming a first geometric anti-reflection (GAR) layer on the first surface, wherein the first GAR layer includes a first plurality of features that have substantially the same height and extend normally from the first surface from a first base located at the first surface to a first tip at a first boundary, and wherein each feature of the first plurality thereof has a first cross-section that increases monotonically from the first tip to the first base, and further wherein the first boundary is characterized by a first effective refractive index that is lower than the first refractive index;
• and
• forming a second GAR layer on the second surface, wherein the second GAR layer includes a second plurality of features that have substantially the same height and extend normally from the second surface from a second base located at the second surface to a second tip at a second boundary, and wherein each feature of the second plurality thereof has a second cross-section that increases monotonically from the second tip to the second base, and further wherein the second boundary is characterized by a second effective refractive index that is lower than the first refractive index.