  Spin and valley flavor polarization plays a central role in the many-body
physics of flat band graphene, with fermi surface reconstructions often
accompanied by quantized anomalous Hall and superconducting state observed in a
variety of experimental systems. Here we describe an optical technique that
sensitively and selectively detects flavor textures via the exciton response of
a proximal transition metal dichalcogenide layer. Through a systematic study of
rhombohedral and rotationally faulted graphene bilayers and trilayers, we show
that when the semiconducting dichalcogenide is in direct contact with the
graphene, the exciton response is most sensitive to the large momentum
rearrangement of the Fermi surface, providing information that is distinct from
and complementary to electrical compressibility measurements. The wide-field
imaging capability of optical probes allows us to obtain spatial maps of flavor
orders with high throughput, and with broad temperature and device
compatibility. Our work paves the way for optical probing and imaging of flavor
orders in flat band graphene systems.
