An optical system, comprising: a hollow mechanical body including first and second ends ; an optical assembly including a plurality of optical components arranged in a stack configuration, each of the optical components including a set of engagement configurations, wherein for each pair of adjacent optical components in the stack configuration at least some of the engagement configurations of a first optical component in the pair are configured to engage with at least some of the engagement configurations of a second optical component in the pair; and an emissive display device deployed at the second end of the hollow mechanical body ; a light-guide substrate having at least two major surfaces parallel to each other and a light-wave input aperture optically coupled to the optical component at the first end of the stack configuration via an optical coupling-in configuration, wherein the emissive display device is configured to generate light corresponding to an image, and wherein the optical assembly is configured to receive light from the emissive display device and output image light for coupling into the light-guide substrate ; characterized in that some of the engagement configurations of the optical component at a first end of the stack configuration are configured to engage with corresponding engagement configurations of the hollow mechanical body at the first end of the hollow mechanical body so as to position the other optical components of the stack configuration within the hollow mechanical body ; and the optical component at the first end of the stack configuration has a prism-shaped cross-section and is configured to modify image light from the emissive display device prior to the image light reaching the optical coupling-in configuration so as to at least partially compensate for chromatic aberration. a hollow mechanical body including first and second ends ; an optical assembly including a plurality of optical components arranged in a stack configuration, each of the optical components including a set of engagement configurations, wherein for each pair of adjacent optical components in the stack configuration at least some of the engagement configurations of a first optical component in the pair are configured to engage with at least some of the engagement configurations of a second optical component in the pair; and an emissive display device deployed at the second end of the hollow mechanical body ; a light-guide substrate having at least two major surfaces parallel to each other and a light-wave input aperture optically coupled to the optical component at the first end of the stack configuration via an optical coupling-in configuration, wherein the emissive display device is configured to generate light corresponding to an image, and wherein the optical assembly is configured to receive light from the emissive display device and output image light for coupling into the light-guide substrate ; characterized in that some of the engagement configurations of the optical component at a first end of the stack configuration are configured to engage with corresponding engagement configurations of the hollow mechanical body at the first end of the hollow mechanical body so as to position the other optical components of the stack configuration within the hollow mechanical body ; and the optical component at the first end of the stack configuration has a prism-shaped cross-section and is configured to modify image light from the emissive display device prior to the image light reaching the optical coupling-in configuration so as to at least partially compensate for chromatic aberration. <EOS>