If you need really high resolution then you have found the right spectrometer!

Customer Comparison; Ocean Optics HR4000 versus HN-9332  Hornet Spectrometer

BONFADINI, SILVIO. "Microfluidic light sources integrated in lab on a chip platforms." PhD thesis, 2019, Politecnico di Milano, Italy ."The spectrometer (HR4000, Ocean Optics) used for the characterization has a resolution of 0.5 nm, that is much higher than the distance between two consecutive modes. This means that the spectra reported so far, are strongly influenced by the performance of the measuring instrument (indeed the spectrum is always the result of the convolution between the signal and the spectrometer transfer function). Therefore, we cannot be sure that our cavity amplifies a single mode or a small range of modes. To investigate this phenomenon, we have upgraded the setup in fig. 3.9 with a new high resolution spectrometer (Hornet, LightMachinery) which, based on an interesting patented technology, has the resolution of 20 pm."

Check out the latest research papers that have been published by researchers using the HyperFine spectrometers here.

HyperFine HF Series Spectrometers

Stunning ~1 pm Resolution or Incredible 30 pm Resolution over the Entire Visible

HyperFine HN Series Spectrometers

Compact Spectrometers for Bright Sources with ~25pm Resolution

Brillouin HyperFine Spectrometer

The Ultimate Brillouin Spectroscopy Tool 

UltraBright Spectrometers

100X the light.  No Slit.  Boom.  Spectrum.  Done

Ultra OSA

Picometer resolution across the entire band in milliseconds

Custom Spectrometers

You won't find these in an optics catalog...  The cool pictures are worth checking out.