An optical system, comprising: a first source generating a first beam (110,112); a second source generating a second beam (108,109); a multi-beam splitter enabled to receive the first beam and the second beam, and further comprising: a beam splitter configured to receive the first beam at a first surface and the second beam at a second surface opposite the first surface, wherein the beam splitter transmits a first partial beam of the first beam and reflects a second partial beam of the first beam, and wherein the beam splitter transmits a third partial beam of the second beam and reflects a fourth partial beam of the second beam; a spot filter comprising an opaque spot having a first radius, the opaque spot arranged coaxially to the second beam to filter the second beam at the second surface; and an aperture filter comprising a transparent aperture having a second radius, the transparent aperture arranged coaxially to the second partial beam to transmit the second partial beam from the first surface, wherein the opaque spot of the spot filter is coaxially aligned with the transparent aperture of the aperture filter and the first radius is equal to or greater than the second radius, and wherein the third partial beam is blocked at the aperture filter. a first source generating a first beam (110,112); a second source generating a second beam (108,109); a multi-beam splitter enabled to receive the first beam and the second beam, and further comprising: a beam splitter configured to receive the first beam at a first surface and the second beam at a second surface opposite the first surface, wherein the beam splitter transmits a first partial beam of the first beam and reflects a second partial beam of the first beam, and wherein the beam splitter transmits a third partial beam of the second beam and reflects a fourth partial beam of the second beam; a spot filter comprising an opaque spot having a first radius, the opaque spot arranged coaxially to the second beam to filter the second beam at the second surface; and an aperture filter comprising a transparent aperture having a second radius, the transparent aperture arranged coaxially to the second partial beam to transmit the second partial beam from the first surface, wherein the opaque spot of the spot filter is coaxially aligned with the transparent aperture of the aperture filter and the first radius is equal to or greater than the second radius, and wherein the third partial beam is blocked at the aperture filter. a beam splitter configured to receive the first beam at a first surface and the second beam at a second surface opposite the first surface, wherein the beam splitter transmits a first partial beam of the first beam and reflects a second partial beam of the first beam, and wherein the beam splitter transmits a third partial beam of the second beam and reflects a fourth partial beam of the second beam; a spot filter comprising an opaque spot having a first radius, the opaque spot arranged coaxially to the second beam to filter the second beam at the second surface; and an aperture filter comprising a transparent aperture having a second radius, the transparent aperture arranged coaxially to the second partial beam to transmit the second partial beam from the first surface, wherein the opaque spot of the spot filter is coaxially aligned with the transparent aperture of the aperture filter and the first radius is equal to or greater than the second radius, and wherein the third partial beam is blocked at the aperture filter. an aperture filter comprising a transparent aperture having a second radius, the transparent aperture arranged coaxially to the second partial beam to transmit the second partial beam from the first surface, wherein the opaque spot of the spot filter is coaxially aligned with the transparent aperture of the aperture filter and the first radius is equal to or greater than the second radius, and wherein the third partial beam is blocked at the aperture filter.